Play your game in Windowed mode instead of Full Screen and you'll be able to move your mouse anywhere. Be advised Windowed mode can be a little more stressful on your card, and that if you have multi~GPU setup ("x2" card, SLI, XFire) you may not receive the benefit of the extra processing.
Also, I've noticed that ATI drivers don't up the GPU clock speed from idle when running games in windowed... might want to find out how to set them to the higher speeds all the time, or find a program that'll up them automatically (I use RivaTuner to raise the clocks once GPU0 has reached a certain threshold temperature).
But yes, windowed mode is the way to go. Especially if you play games using the Source engine... tabbing back into those when they're full screen takes forever.
I hate windowed mode, any other suggestions? Visible taskbar, bar at top, ect. Main game is wow but i'd rather have it work for everything.
Warcraft? Choose Windowed mode, with the sub~choice "Maximized" and you'll get what you want for that game. As mentioned above: If you have a multi GPU setup, this mode will only use one graphics processor.