Although the Eee PC 901 is preloaded with Linux, it's surprisingly unfriendly to get Ubuntu running. A handy tutorial for installing Ubuntu 8.10 on the Eee PC 901 is now online.
Tombuntu did run the standard Xandros-based Linux on his Eee PC 901, but he wanted to run the latest Ubuntu, instead of the standard installation. According to Tombuntu "the laptop is surprisingly unfriendly to Ubuntu despite being preloaded with Linux. Ubuntu 8.10 has delivered some improvements for Eee PC laptops, but it still doesn’t work perfectly out of the box." He did publish an comprehensive tutorial to get Ubuntu 8.10 running, including all hardware tweaks.
Tombuntu reports his Ubuntu system boots in 35 seconds (from Grub to GDM, with SSD tweaks). This is slower then the standard Xandros, but keep in mind that Ubuntu contains a lot more, regarding applications & tools. The default GNOME interface did report 4.5 hours of battery life, which looks very reasonable.