Something that strikes me as odd about today's 'Business Launch' are all the references to Exchange 2007. Unlike Office 2007 and Vista, the Exchange 2007 team hasn't finished their product yet. And don't misunderstand me... I'm glad they're not sticking to an arbitrary date. Just thought everyone should know that you won't find Exchange 2007 RTM on MSDN or the Volume License site.
Here's an official post from the Exchange Blog in case you like to check your sources.