I'm happy to announce that we shipping IE7 Beta 2 today for Windows XP SP2, Windows Server 2003 SP1, and our x64 editions.
My boss, Dean, blogged about the details on the IE blog, so I won't repeat those here.
You can get the new bits on http://www.microsoft.com/ie/. If you have a previous build of IE7 installed, you need to uninstall it first.
Check it out!