I just found this program that lets you do some pretty amazing things while you are in full screen mode in World of Warcraft.
I'm not going to list everything that it can do, but I'm going to give you guys the website. Right now it's in an open beta stage. I'm pretty sure you are going to have to pay for the final product but for the moment it's free.
Here you go.
Just a quick note, as of the moment it doesn't work on Vista or x64 systems. Support is coming soon.