Step1: Take backup of your data if you have any of the linux distros mentioned above.
Step2: Skip this step if you already have Ubuntu 9.1. Install Ubuntu 9.1 (karmic).
Step3: Install oracle 10g as a root user. Problem becoming root? solution follows :
sudo passwd root
su root
Download debian package from Oracle 10g from oracle website (western european).
Double click on it and you will be done.
Install the oracle-xe-client if you want one!
Upgrade your ubuntu to any of the newer version if you want fancy UI and more security.
Any questions? would love to reply to your precious comments :)