Not long after installing Snow Leopard on a multiboot system(using an iATKOS v7 Leopard install), I discovered that the SL partition I made was too small. Currently, I have Snowy set up alongside XP, Windows 7, Leopard, and Ubuntu 9.10. Snowy is set up on the same hard drive as my ext4 partitions.

I read that diskutil is the way to resize the partition: Resize partitions on-the-fly | Utilities | Macworld

Is it feasible do this without reformatting or wrecking the GUID partition table?