The beta servers have just went down and Tigole has posted a quick "patch notes" that have been posted off the top of his head.

Posted by Tigole, (Source )

I don't have patch notes. Off the top of my head:

--Heroics have all been re-tuned. We'd really like feedback on the Heroics this push.
--25 person raids have been re-tuned
--Some tuning changes to 10 person raids
--Many class changes. You won't like the ones made to your own class but you'll think the changes made to the 9 other classes are all overpowered.
--More Icecrown quests and polish. We'd LOVE more Icecrown quest feedback. Please use the in-game feedback UI or post in the quest forums.
--More Dalaran polish
--Performance updates and new performance logging to help get the servers in good condition.
--We're working on getting a beta Glyph vendor in the build so you guys will have quick and easy access to all of the glyphs for feedback. That system *might* make this push.

I'm not the patch note guy but that's my version of the patch notes.