Here's an easy and quick tutorial that'll have you playing World of Warcraft (and a lot of other Windows games) on your Xbox 360 within 10 minutes! I came up with the method, which I've tested and found to work!
1. Make sure you have a computer with Windows Media Center. Windows XP Media Center Edition, Windows Vista Home Premium, and Windows Vista Ultimate are the only Windows operating systems.
2. Select Media Center on your Xbox 360.
If you already configured your Xbox 360 with Media Center skip steps 3-6.
3. Write down the code that Xbox 360 provides. Make sure to keep your Xbox 360 on during this screen and not to shut it off!
4. In Media Center go to "Settings"-"Extender"-"Add Extender".
5. Enter the code from your Xbox 360 and follow the onscreen steps.
6. Your Xbox 360 should boot up into Media Center, this means you've successfully set up your Xbox 360 to work with Media Center!
7. Install the Video recording program Fraps from www.fraps.com, the free trial version can only record 15 seconds at a time so I highly reccomend using Pro.
8. Start up Fraps (on your computer) and make sure its set to save video in WMV or MPEG format.
9. Start up World of Warcraft and make sure to install any required updates before proceeding to step 10. Make sure to install required updates on your PC everytime before you start up World of Warcraft.
10. Make sure you're logged in to WoW.
11. Get a Xbox 360 wireless controller and the required Microsoft software and hardware to configure it with your computer.
12. Make sure to configure your own personal control scheme for World of Warcraft and your wireless Xbox 360 remote.
13. Start recording with Fraps, having Fraps record in higher resolutions will make World of Warcraft look better, especially on high definition TVs, but will cause more lag.
14. Start up Media Center on your Xbox 360 and click on whatever the name the Fraps video is currently recording. Fast foward to the end of the video and the video will keep "renewing" itself since you're watching it as its being recorded.
15. Congratulations! You're playing World of Warcraft on your Xbox 360. This is possible because your Xbox 360 controller's signal is being sent to your computer and the video signal is being streamed to your Xbox 360! Enjoy!!! I'd like to note its impossible for text input on the Xbox 360 controller. You could use a keyboard and mouse to play if you prefer, without any extra configuration, the video will still be sent to your Xbox 360.