Well, you could run in two monitor mode, see:
http://www.ageod-forum.com/showthread.php?t=3162
Or even with a single monitor, the game will continue to run when it has lost focus. So, you could minimize it. Then, you can surf the Web, write some mail, ... while waiting for a turn to compute. If you only have a single CPU which is swamped by the game's CPU needs, you can demote its priority through task manager. Then, you would get priority response from your system for interactive stuff with the game computing during the idle moments.
I hope that helps.