Many distros good for beginners (several listed above) are available as Live CD's. You might want to simply download a few and burn them to disks and then just try them out before installing. Personally, I've found Ubuntu and its derivatives the easiest to use, and the distros which work best with most hardware, though Suse is, so far, my favorite.
LinuxQuestions.org might help you with a lot of your questions. There also is a lot of info there on individual distros.