Here's how to select a Space in Mission Control without leaving Mission Control.
Holding Option while clicking on a Desktop or a Full Screen application will bring that Desktop/Application into focus, but keep you in Mission Control.
This is handy to move apps around Spaces without bouncing in and out of Mission Control.
[crarko adds: I'm starting to really like Mission Control.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20110721081146447