Ok so we all know that the Ubuntu works well on the Beagleboard.
The latest version 10.10 (Maverick Meerkat) even has an official OMAP3 build:
The issue is that this installation is for a full desktop. The meager resources of the BB chugg to say the least with this version.
Best bet is to struggle through the slow full gnome desktop, drop to a shell with Ctrl-f5, login, then stop gdm:
sudo /etc/init.d/gdm stop
then install a lighter window manager:
sudo apt-get install xfce4 gdm xubuntu-gdm-theme xubuntu-artwork