well i think you should get linux. you need to download it though if you want it for free. get a big name distro like mandrake, suse, red hat, turbolinux or slackware if you are only used to windows. i have only used turbolinux and red hat so i know little between the different distros.
for linux training, i find that linuxnewbie.org has a lot of good articles, easy to understand for the beginner, and linuxquestions.org/questions is a really good forum where whatever question you have will usually already have been answered in full. Also, try our very own unix/linux forums here at fuckmicrosoft.com. When i got linux, i read through every single back post in that forum, and it helped a lot.
good luck and hope you enjoy whatever alternate OS you go for!
