I wanted to install Linux into a 15 GB partition. So I made a Boot Camp partition, deleted it in the Linux LiveCD then made a 15GB partition for data and a 1GB partition for cache (as the instructions on the Ubuntu wiki said). After several hours of trying, I gave up since I somehow messed up and I'm too scared of Linux installing over my Mac OS. So now I want those 15 GB back, as I have a 160GB HD and 15GB is a sizable portion. In Boot Camp Assistant it says that it can merge it back with Macintosh HD, but I don't want to risk data loss as I messed up with Time Machine when I had my HD replaced after it crashed. I've attached a screenshot of Boot Camp Assistant.