I run suse linux 9.1 on my laptop dual booting with windows xp on the same drive. The graphic user interfaces are very like windows, it wont take much getting used to! Like you mention there is a lot of free software, some of it you have to work a little to get working... Linux isn't as 'user friendly' as windows, but then it is mainly technical minded people that run it. Progs for windows don't work although you can get an emulator. There are programs available that do almost everything you can imagine, and they are nearly all free and open source!
Anyway, you might want to download openoffice.org first so that at least you can share word/excel files between the two systems...
Anyway, which distribution are you downloading?