An Excellent collection of Exchange 2007 articles
Hopefully everyone is getting excited about Exchange 2007 now!
I know I am :)
Anyway for learning purposes, after the Exchange help file and MSExchangeTeam blog, then it doesn't get better than this:
http://www.msexchange.org/articles_tutorials/Exchange_Server_2007/
There are loads of 2007 based articles so get reading!
Cheers
Nathan