This recent article from the Builder.com.au website shows exactly how simple it is to get a LAMP server up and running on your Ubuntu installation.
I can't tell you how many times I have been asked what is the fastest, easiest way to install a LAMP (Linux Apache, MySQL, PHP) server on Ubuntu. Well, I guess it's time I just post it here for everyone to enjoy.
You're just two apt-get calls and a few various commands away from pulling in an Apache 2 web server and a PHP5 module that has MySQL support already built in. Set the password for the MySQL installation and you're all set to go.