Which WHAT do you need? Firewire cable? If so, most DV camcorders will accept a 4 pin connector while your Mac should take a 6 pin connector. Thus you'll need a 4 pin to 6 pin Firewire cable - a very common item at most any electronics or comptuer store.
By the way, other names for Firewire include; iLink, DV, IEEE1394
-DH