I don't know a lot about the Linux Operating system but I thought I would post a few helpful items that have helped me with my Ubunto Linux installation
Zimbra "is open source server and client software for messaging and collaboration - email, group calendaring, contacts, and web document management and authoring. The Zimbra server is available for Linux, Mac OS X, appliances, and virtualization platforms. The Zimbra Web 2.0 Ajax client runs on Firefox, Safari, and IE, and features easy integration / mash-ups of web portals, business applications, and VoIP using web services."
Ubunto Linix cd. I read a lot of good things
about this Linux distro. Its free (you can even
get the cd shipped to you for free) . [update: I installed this distro and I like it a lot, relatively easy to use and update]
LinuxISO.org A whole bunch of downloadable Linux ISO
distro's
Damn Small Linux What is Damn Small Linux? Damn Small
Linux is a business card size (50MB) bootable Live CD Linux distribution.
Despite its minuscule size it strives to have a functional and easy to use
desktop.
Wanna play PC games on your Linux??? Check out Cedega's TransGaming
Technologies. You will need to pay for a subscription though : (
See this cool video of what Linux can do. See the video's on this page featuring "wobbly windows" which is a cool window effect that doesn't need a lot of expensive hardware to do. Warning they use MPEG4 for the video format which you will need a special plugin for Windows Media Player to play. Though Linux Firefox does it naturally. You might want to download the new Divx Player to play it in Windows. [recommended, cy]
Here is a pretty decent video on installing stuff on linux
As you will see installing programs in Linux can be a major pain in the ass. It can get really involved especially when you have to start using the command line. This 13 minute video can be summed up in Windows by saying "double click the .exe file". Which pretty much explains why 95% of the worlds computers use Windows and Linux remains "exclusive" to eggheads.... sigh.