I know closing the lid on the old MacBook would completely put the Mac to sleep. However, on the MacBook Pro you can close the lid and continue to use the Mac with an external screen. I haven't found this specific information covered. I did find that the Mini DisplayPort to Dual-Link DVI Adapter page on the Apple store reads, "You can use an external display as your main workspace or to extend your desktop, or you can work in mirrored mode with a projector so you can view what your audience sees." Can someone confirm that an external display can be used with the 13-inch Aluminum MacBook's lid closed. Thanks.