Hi, sorry if this has been brought up but I'm need of help fast. I have a My Book external hard drive and I have an new iMac with Leopard and a Vista PC and need both computers to be able to write to the My Book drive. The My Book drive has both Firewire and USB so I can connect both computers simultaneously but is it possible for them both to write to the drive or can it be only formatted to work for one OS at a time? I am buying it today so I wanted to know what my options are in the scenario? Any help appreciated.