Hack Attack: A guide for switching to a Mac - Lifehacker

This is a very good Switchers guide. If I may add one tip, it would be a substitute for the "up one level" button in Windows. Mac OS X doesn't have such a button, only forward and back. But, there is a keyboard command which I use all the time:

Cmd-"up-arrow"
(Hold down the CMD/Apple key and hit the up arrow.)

Viola, you have navigated up one level! And, once you get used to that, you may want to start using CMD [ and CMD ] to navigate back and forth.

Hack Attack: A guide for switching to a Mac - Lifehacker