Wow! I just installed this and have already regained 7.2 GBs and it's not even done! And in 15 minutes!
Squeeze is a preference pane (in your System Preferences) that runs in the background and auto-compresses your files using Snow Leopard's new compression technology to compress your files without deleting media or limiting your abilities at all. It runs in the background, using only free resources on-the-fly to keep you working. Your files work as usual, but it just shrinks their hard drive footprint. While I would advise against using this on things like your Avid and FCP projects, because you can ill afford one bit of data corruption, I've been using it on my FCP Documents folder, Applications, Movies folder, and am still adding other stuff too!
Usually this software is $10, but for TODAY ONLY, you can get a free license through MacHeist. Just visit the site and create an account with MacHeist. This place is awesome to begin with, but today is a extra-special day!