Have you used windows before? If so I would recommend first try kubuntu

Here is one guide:
http://books.google.com/books?id=kHL...age&q=&f=false
"pocket" version...makes me laugh ~160 pages, but just look for what is important. Quite a lot extra stuff there.

.edit
And oh. Test stuff form live-cd's. You do not have to installm but of course please remember that some apps load quite a lot when used from cd.