If you want to try Linux, I would suggest running one of the bootable distros such as Morphix or Knoppix. They boot directly off the disk and you don't have to install anything.
If you are a beginner at Linux, I would suggest a distro such as Lycoris desktop/lx, Lindows or Xandros. As you get more "experienced" at Linux, you should try Red Hat Linux or MandrakeLinux. If you really feel confident, take the plunge and install Linux without a GUI (Graphical User Interface).
I remember my first Linux distro... Red Hat Linux 7.1... And I remember the trouble I had trying to get it to recognise the NTFS system I had installed Windows 2000 under... Ah, it was bliss, me and my command line, trying franticly to find the correct command in the user manual, giving up in despair and just reformatting the whole drive, and finding out that I forgot to backup my stuff... (Now that I think of it, Red Hat Linux 9 isn't much better at recognising NTFS than 7.1
Welcome to Linux!