Selenium is written in Java. So you need Java. Ubuntu users should already have Java installed (
Then download the latest Selenium Server jar file from http://seleniumhq.org/download. Put it anywhere. You can run the server with this command:
java -jar selenium-server.jar -h
Xvfb or X virtual frame buffer is an X server that enables you to run X windows applications without showing any screen output. If you run this with a Selenium server, you can run your tests on various browsers on a server with no monitor and without X windows installed. See an example of how to do this in Test::WWW::Selenium::More::Manual::RunningTests.
To install Xvfb on Ubuntu:
sudo apt-get install xvfb
Eric Johnson <kablamo at iijo dot nospamthanks dot org>
This software is copyright (c) 2012 by Eric Johnson.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.