You need a Analogue to Digital convertor. The easy way of doing this is borrowing a DV camera, connecting the AV out from the old camera into the AV-in on the DV camera and copying the clips onto the DV camera. Then you can import with Firewire as normal. Some cameras will act as a proper A-D convertor on the fly, ie. you connect the computer directly to the DV camera and will stream the digital signal directly to the comp. However this is more suspectible to dropped frames etc, and you only save a bit of time.
Alternatively I know some expensive PC tv/graphics cards can handle AV in, which will grab an AV signal in real time, but I've never tried to do this on a Mac.
