Here’s a quick tip if you need to re-size a partition in Mac OS X WITHOUT destroying its data. Usually, you would get the commercial software iPartition – which, by the by won’t let you re-size the disk from which you are booting, you need to create a boot disk and whatever.
However, I just discovered that diskutil has a hidden command option. Yey! (Thanks to some internet dude, of course).
Open a terminal, do a “sudo bash” and then type “diskutil resizeVolume”.
You will be prompted with some text telling you how to use the command. I just ran “diskutil resizeVolume /Volumes/VolumeToReisze 200G” where 200G is the new size I want for my partition. It took a few minutes; after that I created a new partition in the empty space using the GUI version of diskutil, Disk Utility.
And that is that. Oh, this only works for Tiger and later. You are telling me you are still on Panther? Wow, dude… upgrade your OS.