Apple has released to important updates: one of them is the Boot Camp 3.3 update, and the other is an iMac graphics firmware update.
Boot Camp is Mac OS X’s tool to help you run Microsoft Windows on your Mac. Critical bug fixes and hardware support is bundled in this update. It requires Windows 7 and Boot Camp 3.2
There is also an iMac Graphic FW Update 3.0 which fixes issues where some iMac users, who upgraded to OS X Lion, found their computer freezing during playback of certain videos/movies. They were forced to do a hard shut-down. This update fixes this bug.
Grab the update by either running Software Update or by going to Apple’s official downloads page.