FireWire 400 has two connectors: 6-pin (what Apple puts on all its FW devices and computers), and the smaller 4-pin, which is what DV camcorders and many PCs use. Assuming the drive uses a 6-pin connector, just get a cable with a 6-pin on one end and 4-pin on the other (these are the easiest FW cables to find, frankly).
tooki