Here's how to install the AppleTV with the Broadcom chip. It looks like a lot, but shouldn't take much more than an hour.
1. Set up the Apple TV normally, go through the welcome crap.
2. Install XBMC with the Patchstick creator (piece of cake - make sure you use a fresh USB stick, it will format it)
http://atvusb-creator.googlecode.com/fil...in-3.0.zip
3. Test out XBMC - there will be a new menu in the Apple TV software called "Launcher". You can use Launcher to install XBMC. Download and install.
Now that we can run XBMC let's install the Crystal HD hardware and software.
4. In the AppleTV menu go to \Launcher\Downloads, and use that to update Launcher itself to 3.2.4
5. Follow this thread to add some extra entries to the \Launcher\Downloads menu. Will let you get daily builds of XBMC;
http://forum.xbmc.org/showthread.php?tid=67078
6. Install the latest daily build of XBMC. (Currently 26928)
7. Follow this thread to add the Crystal HD driver to the \Launcher\Downloads menu.
http://forum.xbmc.org/showthread.php?tid=69321
8. Install the Crystal HD driver using \Launcher\Downloads (currently r26)
9. Physically install the Crystal HD hardware (only follow the hardware instructions, don't do anything it tells you with the software!)
http://www.blogythefox.co.uk/2010/01/09/...tallation/
10. Test out XBMC with a 720p .mkv. Download an episode of the Simpsons for a test file that will download quickly because of all the seeds.
That should be it.
Oh yeah, you'll need Putty to do the SSH commands into the AppleTV box as mentioned in the links above. Putty is free here;
http://www.chiark.greenend.org.uk/~sgtatham/putty/