Linux for the most part is a totally different animal from Windows. I can easily list some of the smaller and easier distros to get familiar with. Before proceeding with installing any Linux distro however you will want a partitioning tool that can later remove a Linux partition as well as create it.
The Gnome Partition Editor known as GParted Live for cd can also create NTFS and Fat32 partitions as well as the VFat used for Linux. Besides the different download links at the link here you will note the tutorials, screen shots, and other links in the left column at
http://gparted.sourceforge.net/download.php
There are several like Knoppix Live for cd that DO NOT require installation to the drive at all. You simply burn the iso image to a boot cd to load the distro without making one change to your system. These are self contained OSs that run from the bootable media rather then altering the present system. GParted is still a good one to have onhand as far as a "Free" partitioning tool and can remove RC1 later when you decide to remove the beta version.
Knoppix a favored for retrieving files off of Windows as well as Linux drives also has a few companion live distros like Zenwalk, Gentoo, ubuntu, Mephis, and a few others. I'm not sure at this if PCLinux has one to offer as well.