Sorry for getting so techie lately, but I think I may be able to help here.
Before you go Linux, if you've been thinking about it, know that there's a lot of hype around it. We're still talking about your computer being a tool and not some mystic way of making people happy and good towards one another. It has limitations -- like any system -- and jargon and concepts -- like any system -- that without which you'll never get on with Linux. For my purposes, I'll be referring to Ubuntu Linux, since I'm still new with it and since it looks like it can offer the everyday user just about everything.
First, there's no C drive or D drive or any lettered drive. The rough equivalent on my machine is /home/scott and if you come over for the weekend and need to check your email I'll set up /home/guest for you. Most of the software lives in a top-level directory called /bin/ and drives are "mounted" at /mnt/, as in /mnt/cdrom and mnt/flash/.
Next, and not to make this too difficult, but there are two common ways to add all that lovely free software you've heard so much about. The Fedora/Mandriva side of things use bundles called RPMs and I found them terribly unmanagable. Distributions, like Ubuntu and Mepis, built on Debian Linux get the software from repositories with a piece of software called
apt-get. I mention it because this is turned into a verb constantly, and you need to know Ubuntu has a graphical front-end called Synaptic Package Manager that'll take care of you apt-getting for you. I already used it to get gFTP (for FTPing), Audacity (for creating audio files), Bibletime (with King James version) and Scribus (for proper desktop publishing).
But getting the free-of-charge-but-not-open-source Flash animation software took going into a terminal and using a command line. That's the DOS-y bit for Windows users. More about that later.