It's a new launcher Blizzard's trying out that will allow you to log-in to WoW, Diablo 3, and Starcraft 2 all at once. Then you just click on the game you want and hit play to open it. It's really pretty nice.
Here's a look at it:http://i223.photobucket.com/albums/dd11 ... 922639.png
And according to the e-mail Blizzard sent out, we get something cool for beta testing the launcher:
As a beta tester, you'll be able to download an early version and provide feedback. In addition, closed-beta invitees who download and use the app during the closed-beta period will receive something cool from Blizzard and the Battle.net team in thanks.