The recent patch makes most guides outdated, but i still suggest reading this article. it may give you ideas.
The most important difference is that defense is no longer a visible stat, and you reach "uncrittable" via talents.
but most other things are still valid, at least until Cataclysm hits.
Oh, and also, congratulations on your group of friends. It's nice of them to help you catch up to play with them in the new expansion.
If you go to http://www.wow-heroes.com after entering your realm and character name will display a bar that will give you an idea of what current raids you can play with your current gear, gems, enchants, etc.