Hi,
I'm glad that you are trying out Linux. I think that it is a great alternative to Windows, and it is certainly a very powerful operating system.
Firstly, I would like to explain a few things. Linux itself, is a command-line operating system, much like DOS. However, it had since had many GUIs written for it, the most popular two being KDE and Gnome.
KDE is quite similar to Windows in it's layout, and so if you have not used Linux before, I suggest a distro which has KDE as it's default environment.
Kubuntu [which runs KDE] screenshot, click it to view more.
Gnome, is also easy to use, but it does take a while to get used to it. Here is another screenshot:
Ubuntu, which runs Gnome.
For your first steps in Linux, I suggest that you try either Ubuntu [
http://www.ubuntu.com/] or Kubuntu [
http://www.kubuntu.org/]. Both of these can be downloaded for free and burned, and you simply reboot your PC and you can use it in a "live CD" mode, which means that the OS will run from your CD-ROM and RAM. Of course, if you decide to install it to your hard drive, it will run much faster [you can also dual boot both Windows and Linux].
If you have any more questions then feel free to ask them.