[spoiler]What you will need.
1. A No Pass device. This is the newest generation of Passme devices. They are a DS cart that goes in your DS cart slot and removes the security checks of the DS firmware, allowing you to run unsigned code from the GBA slot. They are very simple to use. Just put it in your DS slot like a game, and away you go. No need to flash your DS's firmware like with the previous generation of Passme's. The Superkey, Passcard 3, and MK4 - Mini are the currently the best ones on the market.
2. A GBA flash cart. This is a cart that goes in your GBA slot and works as an adapter for flash media (CF, SD, MiniSD, or MicroSD). Basically you load the files onto the flash media on your computer, pop it into the GBA flash cart, and run the files from there. There are many different carts on the market of various sizes. Different carts have different compatibility with homebrew, DS backups, and GBA backups, so it is important to do a bit of research before buying to find the cart that fits your needs.
Right now the two best all-round carts are the Supercard and the M3. The M3 has a nice GUI loader and slightly better GBA backup compatibility. The Supercard has a simple text based loader, and slightly worse GBA backup support. Both have about the same compaitibility with DS backups and homebrew. The M3 is almost 2x the price of the Supercard, so you will have to decide for yourself if the GUI and slightly better GBA backup support is worth the extra money to you.
Some carts, such as the G6, have internal memory so there is no need for extra flash memory such as an SD card. This type of cart currently only has up to 512MB of memory, however. That's probably enough if you only plan on using it for backups, but if you plan on running a lot of homebrew, MP3's, and videos, you will find it to be not nearly enough room.
3. If you went with a cart without internal memory (such as the M3 or Supercard), you will need flash memory of your choice and size matching the format of the cart you got (for instance, if you got the Supercard MiniSD, you will need a MiniSD card in the size of your choice). You will also need a USB reader to read the card on your PC.
Here are a few links to the homepages of just a few of the more popular carts for the DS:
Supercard:
http://www.supercard.cn/
M3:
http://www.m3adapter.com/
G6:
http://www.g6flash.com/
EZ-Flash:
www.ezflash.cn/en/
Neoflash:
http://www.neoflash.com/
Where to buy.
I would recommend buying from a place based in North America or Europe over a place in Asia. The Asian places get the new products a fair bit earlier, but can be quite untrustworthy. Better to wait a few weeks longer and get it from a more trustworthy source. I've got all my stuff from Kicktrading (
http://kicktrading.ca/). Great customer service and fast shipping. He's based in Canada, but ships worldwide.
There is a fairly definitive list of shops and reviews on GBAtemp here:
http://gbatemp.net/index.php?showtopic=33039
Flashme.
Flashme is a replacement firmware for the DS that doesn't have the security checks built in, allowing you to run unsigned code from the GBA slot. You will still have to purchase a No Pass device as described above to install it. Be aware that many people have bricked thier DS's trying to install it, particularly the Lite. However, if you follow this giude, you should be ok:
http://gbatemp.net/index.php?showtopic=33481
Pros and Cons of Flashme:
Pros:
1. No need to have a No Pass in your DS slot. Helpful if you have lots of legit games that you will be swapping out.
2. Writes recovery code into your firmware, enabling you to recover from viruses.
3. Saves a small ammount of battery time because you can have nothing in the DS slot.
Cons:
1. You can brick your DS trying to install it and a lot of people have done so.
2. Voids your warranty.
3. Not really needed anymore with the new No Pass carts.
Some people like to use flashme because it checks for the only DS virus and they feel it makes them "safe" from viruses. Personally I think it's not needed. The virus was only released as a proof of concept and only got 5-10 people, and that was about 6-8 months ago. No one has seen it since.
Whether you have Flashme or not, the best way to protect yourself is to only get your homebrew from reputable sites such as the ones posted futher down in this guide, and let others test it first and report back. Wait a few days to a week after it is posted and read the comments, making sure it is safe. I followed this practice with my Flashme'd DS Phat, and I follow it with my non-Flashme'd DS Lite with No Pass (Superkey) as well. My point is that you are dreaming if you think Flashme is going to keep you safe and protect you from viruses. Only being a smart user will. This is why I think Flashme is not needed as protection from viruses.
Personally I think the No Pass is the way to go. You already need it to install Flashme anyway. Why void your warranty and risk bricking your DS when No Pass works so well?
A little more info on the virus for the DS:
http://wiki.pocketheaven.com/DS_Bricker
Homebrew Apps.
There are a lot of really great homebrew apps available for the DS. There are two that I think are must - have for any DS owner, Moonshell and DSOrganize.
Moonshell (
http://mdxonline.dyndns.org/archives/nds/ ) is an all in one file viewer and media player. With it you can listen to MP3's, watch movies, view pics, and read .txt files. It is highly skinnable and customizable. It can be complicated to set up until you know what all the settings do.
Here's my skin and compile with LE5 skin for those of you who either want the skin, or would like to give Moonshell a try, but don't want to go through the trouble of compiling it.
Screenshots:
Kit for compiling your own (
http://www.megaupload.com/?d=VRQVMMOD ).
Self contained .NDS files of the lasted version of MoonShell (1.33). Just send them to your cart and run them. No setup needed. (
http://www.megaupload.com/?d=UIA2897I )
The black version looks a little bit "grey" on the Lite with full brightness due to the insane brightness of the Lite. Maybe I'll make a version made just for the Lite with full brightness when I feel motivated and if there is demand for it.
DSOrganize (
http://www.dragonminded.com/?loc=ndsdev/DSOrganize ) is an organizer app for the DS. It has a Calendar, Day Planner, Address Book, Todo List, Scribble Pad (paint), File Browser, Calculator, and Homebrew Database. The file browser is much more robust than Moonshells. It allows you to create and delete files, hide and unhide files, view .txt files and add bookmarks as well as edit them, and view and edit HTML files. One of the best things about it is the Homebrew Database. Though it only has a small percentage of what is out there, it allows you to download apps over Wifi right onto your DS. Awesome stuff!!
I have compiled a small list of homebrew apps. This is by no means a definitive list, but there is more than enough to keep you busy for quite some time.
This has everything to do with Homebrew - No Warez or Roms
MoonShell (Media player and file browser)
http://mdxonline.dyndns.org/archives/nds/index.html
BatchDGP v1.0 (High Quality DPG Converter for Moonshell)
http://ls5.cydonianknight.com/
DSOrganize (Organizer and file browser)
http://www.dragonminded.com/?loc=ndsdev/DSOrganize
DSLinux (Linux on the DS)
http://www.dslinux.org/
beup (MSN client)
http://forum.gbadev.org/viewtopic.php?p=83323
PicoDriveDS (Sega Genesis Emulator)
http://forum.gbadev.org/viewtopic.php?p=86430
NDSMail (Email and RSS)
http://blog.bronto-online.de/
Draw (R10 - Powerful Paint Program)
http://blog.davr.org/category/nintendo-ds/
SnezziDS (SNES Emulator)
http://www.forwardcoding.com/project.../snezzids.html
Mini vMac DS (WIP MiniVMac emulator)
http://lazyone.drunkencoders.com/wordpress/
DSAIM 0.01e (AIM Client for the DS)
http://forum.gbadev.org/viewtopic.php?t=10566&start=0
ReinMoon v0.4 (DS Cart Save Backup Tool)
http://mdxonline.dyndns.org/archives/nds/
Dillama 0.1 (DS XBMC Remote)
http://forum.gbadev.org/viewtopic.php?t=10485&start=0
DualSwan/WonDerS (WonderSwan emulator)
http://liranuna.drunkencoders.com/
Win2DS (Control your PC with your DS)
http://www.1emulation.com/forums/ind...howtopic=16875
DS2Key (Use your DS as a PC game controller *perfect for emu's*)
http://www.1emulation.com/forums/ind...howtopic=18499
Stella DS (Atari 2600 emulator)
http://thechuckster.homelinux.com/stellads/
Project Liero DS (Worms clone)
http://lierods.com/
Wolfenstein 3D (Wolf3D port)
http://lazyone.drunkencoders.com/
A Touch of War (RTS Game)
http://www.atouchofwar.com/
DS Drum Machine (909 and 808 emu)
http://thechuckster.homelinux.com/tr909/
Dissonance (streaming media)
http://grey.drunkencoders.com/
SylphAMP (Control Winamp from your DS)
http://www.sylphds.net/ev2/contentview.php?id=462
Dualis (DS emulator for the PC)
http://dualis.1emulation.com/
Yet unnamed RTS Project (WIP RTS game)
http://mightymax.org/unnamed_strat.html
ScummVM DS (ScummVM emulator)
http://scummvm.drunkencoders.com/
AXE (Electroplankton inspired game)
http://forum.gbadev.org/viewtopic.php?p=81973
Poke Teh Bunny (Poke the Bunny. Careful! It bites!)
http://liranuna.drunkencoders.com/?page_id=22
SylphIRC (IRC client)
http://www.sylphds.net/ev2/contentview.php?id=401
flashbackDS (REminiscence Port)
http://gtamp.com/DS/flashbackds.htm
NitroTracker (Powerful tracker app for the DS)
http://nitrotracker.tobw.net/
Super Snake DS (Snake for the DS)
http://forum.gbadev.org/viewtopic.php?t=10382&start=0
Tales of Dagur (RPG)
http://liranuna.drunkencoders.com/
DrummerS (DS drumkit)
http://www.lien.palib.info/nds/proy.html
MegaETk (MegaMan Clone)
http://etk.scener.org/
robotfindskitten DS (robotfindskitten)
http://gpf.dcemu.co.uk/robotfindskitten.shtml
Bubble Wrap DS (Who doesn't love to pop bubble wrap?)
http://teamnnc.free.fr/phpBB2/viewtopic.php?p=6827
NetHack DS (NetHack Port)
http://stuartp.commixus.com/nhds/
Suomitetris DS (Tetris clone)
http://kotisivu.dnainternet.net/ttil...is_DS/main.htm
QBX (3D cube 5x5x5)
http://forum.gbadev.org/viewtopic.php?p=91745
Twin Isles (Sim Isle clone)
http://h4ck3r.net/
Puerto Rico (Fun little game)
http://69.246.215.52:8181/prds/
Command and Conquer DS (WIP C&C Port for the DS)
http://cncds_project.livejournal.com/
Links.
GBAtemp (Flashcarts, homebrew, reviews and guides):
http://gbatemp.net/index.php?act=home
gbadev (Homebrew and development):
http://forum.gbadev.org/index.php
The Unofficial Supercard Forums (Supercard and homebrew):
http://scdev.org/forum/index.php
M3 Adapter Forum (M3 and G6):
http://www.m3-forum.com/index.php
GBA The Movie Way (Movies, Homebrew, M3):
http://gbatmw.net/
Drunken Coders (Homebrew):
http://www.drunkencoders.com/
What Alice Found (Homebrew):
http://ds.whatalicefound.net/news/
Dualscene (News and misc.):
http://www.dualscene.net/news.php
DS Linix (Linux for the DS):
http://www.dslinux.org/
EZ-Flash Froums (Official EZ-Flash English Forums):
http://ezflash.sosuke.com
Guide updated 30/07/06