Virtualization is a very handy thing. It allows users to run a computer within their computer at nearly full speed in most cases. These computers are not limited to the same type of computer as the host either. A PC can run a Mac, and a Mac can run a PC. Microsoft's Virtual PC 2007 is their contender for virtualization.
Freeing your mouse
Press the "right Alt" key. This is the standard way to release the mouse cursor from the window in Virtual PC 2007.
Press "Ctrl Alt Delete" to bring up the "Windows Security" panel. this will break the mouse out of the Virtual PC 2007 window as well.
Press "Control Option Left Arrow" or "Command Period" to release the mouse from the Virtual PC window on a Macintosh computer.