www.biztechmagazine.com/article.asp?item_id=324
Here is a pretty good article.
I have personally went though this process to get us up to 2008 r2.
I have done allot of these so I never personally followed this guide, but its looks pretty complete.
I had extra steps not listed in this guide. Someone before me installed exchange and a domain controller on the same server....
So basically the guide looks good but if you have something fishy in your environment you'll have more steps than this guide supplies.
