XDA member bobdude5 brings us this great tutorial on how to run Ubuntu on the EVO. The instructions seem to be rather simple to follow, but knowledge on how to push via adb is required. As I have not tested this build myself, there are things (as with any port) that may not be functional. The thread, which was started in July, has quite a bit of feedback so far, so make sure you go through at least a few pages to see if it is worth the effort to have this on your EVO.
If you can contribute to the project also, feedback is always welcome.
First you have to flash this zimage
Do this by rebooting your phone into fastboot
fastboot flash zimage zImage
then reboot and follow the instructions on this tutorial and it will work like a charm
You can find more information in the port thread._________