ok, seems everyone here is a bit confused.
1. I have NEVER seen a miniDV camera that DOESNT have firewire. It just doesnt look like the FW port on your mac. You need a 4 pin to 6 pin FW cable. (the 4 pin -small- end goes into the camera, and the 6 pin -large and looks like the port on your mac- goes into the mac). Sony calls it iLink on the cameras. Also called IEEE1394 (firewire is an apple name, so to call it FW sony would have to pay apple. So they call it something else, but its the same).
2. You need to turn the camera to VTR mode (the mode you have it in to watch the tape on the camera screen).
3. The camera needs to be in VTR, plugged in AND turned ON BEFORE you launch iMovie. (if you turn on the camera AFTER iMovie is launched, it wont recognize it)
4. iMovie has a small slider that looks like a film clip on one side, and a camera on the other. Slide it to the camera icon side.
5. Most cameras will be controlled via the iMovie interface at this point. Meaning you can play, pause, RW, FFW from the buttons in iMovie.
6. You should see your viewer window go BLUE, press play (either on iMovie controller, or on camera) and click IMPORT.
7. let the full amount of footage you want to import play (it will do so in real time, so if you shot 25 min, it will take 25 min to import.)
8. When finished click ESC (or done) in iMovie and it will stop the import and camera.
9. Slide the slider BACK to the film strip icon in iMovie and you will then see all the footage as little clips on the right.
10. edit and enjoy
You should NOT be capturing from a miniDV camera via USB. EVER. forget the camera even has the port on it. It is mainly for cameras that also take stills and store them on a separate memory card. The data transfer rate is not fast enough to capture DV footage on anything other than FIREWIRE.
if you do have a new macbook with no firewire port, i have heard there are FW to Ethernet adapters that may work.
(some of my naming may be a bit off depending on which version of iMovie you have, as I have not used iMovie in several years.)