For all those who don't know, check out the official site at:
This fan made game takes place before the first X-box Halo game, and is actually very good. Think NES Contra with Castlevania Sotn quality graphics.
You can download it for PC through the main site, if you'd like to chack it out... They've even made a level editor for your creative needs. I just thought I'd share this with everyone here, besides that it would no doubt make an excellent game port for the PSP.
I will upload pictures soon...meanwhile you can go check some out at the site.