Yeah, enjoy your stay in Linuxworld!
Wade around in Mandrake until you get comfortable before messing with Debain. In all reality, it's probably best to go to Slackware next, since it's a great place to get a Linux 'crash course'.
Just a few suggestions to keep in mind when playing with Linux.
1) Read the READMEs. You could skip reading them in Windows for the most part, but they are absolutely essential in Linux. At least read the parts about installation
2) Man is your best friend. When you need to know what a particular command or configuration file in the /etc folder does, 95% of the time you can type:
man
command
in a console window and get a very informative article on it's use. Sometimes a little too informative, however. Don't let it intimidate you, it's invaluable.
3) Learn the ways of the Internet for help. Sites inparticular to pay attention to:
www.linuxjunior.com www.linux.org www.linux-tutorials.info www.mandrake.com <Official Mandrake website of course
www.techimo.com < A definate
4) Patience is a virtue. If you somehow screw Linux up beyond repair, or at least beyond your ability to repair, just reinstall. For that reason, it's best not to put anything really important on Linux until you get comfortable with it. If you have to do things like projects or checkbook balancing, save them on MSDOS-formattted flopy discs, CDRWs, or if you are dual booting, on your windows hard drive.