Any help about my previous subject: ubuntu?

http://www.who.is.free.fr/wiki/doku.php?id=rootfs
RTFM!
Its not installed on device, but its running from NFS(there is manual how to install and appropiate image of rootfs). It's also very datee, and not sure if it's using xmim vkb, probably n950 only.
There are already scripts fir running Debian, Ubuntu is a fork, so it's very similar.
I don't want to be rude, but believe me that if you are to lazy to install it, then you will never be able to make anything usable from it.
Installing(natively/to chroot) another linux distro and starting it is the easy part. But porting all the quirks and workarounds is hard part of the game (VKB for n9, touchscreen, lower DPI and different aspect ratio(especially on n9 with VKB), tuning PulseAudio, etc).

At 1st I don't understand why do you want Ubuntu, when there's EasyDebian already (after installing Ubuntu theme, you will see virtually no difference. In N900 case with HDMI out and USB OTG it makes some sense for typical full desktop experience. Even on beginning of page you provided link is written that rzr started with ubunto test and port it to Debian Wheezy...