I just did it yesterday - worked great.
1. Dl the whole Xbox Linux Mandrake 9.0.zip
2. Burn both CDs (Boot, and Install)
3. Insert Install CD, reboot - boot whatever
4. Type setup (for 10gb hd) or setup8 (for 8gb hd)
5. Wait, wait wait.....
6. When install is finished insert boot CD and restart.
You can also copy the 4 files off the install cd on to your HD and use evox to launch it instead of the boot cd.
You may also want to back up you HD before installing.
I did the install on a 10gb hd and x-ecutor chip. Works great.