For someone just looking to learn/play with different Linux distro's I'd recommend a different route than setting up one physical box for this. If you have a decent system running (as I have to assume you do), go to www.vmware.com
, navigate to the Free Virtualization Software section and download VMWare Server (free of course). You'll have to register with them to get the FREE code(s), but it really is free. I use that to test different operating systems on my physical boxes as well as run dedicated task servers. Such as one VM for my FTP server, one for my digital gallery (for my photography), one for my SAV server. I'm in the process of setting up one blog server as well as working on configuring an email server. All are virtual (all running Linux distro's except the SAV server with is running Windows Server 2003 Standard edition). A high benefit of this method is you can backup the entire VM to another system, or media (tape, etc.) and not have to worry about a hardware failure cauing you XX hours of work to rebuild your Linux boxes. I actually just upgraded one box to CentOS 5 (64 bit version) and had to work on getting a video card that could feed my 24" LCD. Now that it's running, I simply copied back my VM sets (each VM gets it's own directory within the VM directory on your hard drive). All I had to do then was browse to them from within VMWare and tell it to open them up. Now I'm running my SAV server, web server, anfd FTP server just like I was before.
If you want to have an even better experience, install Linux as your boxes main OS (I'd use either Fedora Core 6, or 7 when it's been out for a while, or CentOS 5) and then install VMWare on it and then make your guest systems. With Linux having less overhead when compared to windows, it will make for a leaner system. Besides, both Fedora Core and CentOS are free distributions.