Recently managed to setup an Ubuntu 10.04 server for my business Black Box Innovation Technologies (http://www.blackboxitech.com). It uses LAMP (Linux, Apache, MySQL, PHP) for our hosted websites.
There were some things that I had to learn since the websites that we host were on a Windows XP based computer using XAMPP.
I'm currently trying to add more features to the Linux server, including a mail server and LDAP server, but I'm currently having trouble doing so. I've looked everywhere, but the tutorials do not seem to be of much help. Hopefully I will figure out soon.