I've messed with Linux several times as a complete newbie. I never did anything with the installation (it always left me with "Ok, so now what?" kind of thought), although I'm about to start again...
the point is that even for a complete Linux newbie like myself, installation with new distributions is ridiculously easy. I tried TurboLinux, Mandrake and Slackware, Mandrake being the easiest for me...
In Mandrake, the software will do everything for you -- repartition the drive (just make sure you defrag it first), format the partitions for Linux (swap, boot, home & root), and make a dual or triple boot manager yourself -- when I boot the computer, I just choose between Windows & Linux.
The whole installation took 30 minutes on my k6-233.
Now, it may not go AS smoothly for you, but all in all it is usually painless...
So, you can stick with one drive, or have two if you want to, but there's no reason for you to go through BIOS -- LILO (boot manager which comes with linux) works perfectly.