Installing Oracle on Ubuntu is fairly easy, since Oracle has created a Debian and Ubuntu package repository, so it is possible to download and install the Oracle database software using apt-get and aptitude.
Howto use the Oracle Debian and Ubuntu Repository
Add the following lines to the /etc/apt/sources.list
tux@earth:~$ sudo vi /etc/apt/sources.list
....
# ORACLE CLIENT
deb http://oss.oracle.com/debian unstable main non-free
The installation process might report that the Oracle packages are not gpg signed, but you should be able to install the packages anyway.
You can avoid this report by added the Oracle gpg-public key to your apt-key chain
tux@earth:~$ sudo wget http://oss.oracle.com/el4/RPM-GPG-KEY-oracle -O- | sudo apt-key add -
Update the package repository database with
tux@earth:~$ sudo sudo apt-get update
Now you should be able to install the following Oracle software
tux@earth:~$ sudo apt-get install libaio oracle-xe-client oracle-xe
Configure, you have to entered the password for the SYS and SYSTEM user.
tux@earth:~$ sudo /etc/init.d/oracle-xe configure
Access the nice Oracle web interface by pointing your Firefox to
tux@earth:~$ firefox http://127.0.0.1:8080/apex