Apple uses a powerful magnet to release these latches, but the official tool is not available. If you have access to a few failed hard drives, you can take out the magnets from those, and stack them up to have a magnet strong enough to easily open these latches.
Simply place the magnet on an upper corner of the machine, and when you hear a click, gently pull the corner of the front case forward. Repeat the process for the other upper corner. Use care not to pull on the iSight cables.
Note: Use care when handling the hard drive magnets, they are powerful, and you don't want them to snap together on your fingers. OUCH!