If anyone plans on multiboxing on a mac (especially a notebook) I highly recommend the utility SMCFancontrol. It's a freeware utility that adds a temp/fan speed gauge to your menu bar so you can force the fans to run faster than the SMC on the board would bu default.

Macs in general are tuned for a quieter fan rather than keeping things as cool as possible when playing 3D games, so if you want the computer to last longer and run cooler use this to crank the fans up while boxing:

http://versiontracker.com/dyn/moreinfo/macosx/31029