Unfortunately, the Hydra software is Windows only at the moment. I have read about people successfully running it through VirtualPC, but your mileage may vary.
Are they the older PowerBooks with serial ports or the newer USB-only PowerBooks/iBooks? Regardless, you will need to somehow work out having a DB9 serial port to connect to the Hydra. They don't recommend USB/Serial converters, but some have been known to work successfully with it anyway.