Welcome to iMovie Discussions.
The
PV-GS400 should work perfectly well via its FireWire port.
(The USB socket is for transferring only stills from this camera, not video.)
"..I don't have a DV line currently to try it, looking for information before I purchase one.." ..er? D'you mean that you don't have a FireWire cable to use with this camera..? If so, any brand of
4-pin-to-6-pin FireWire (..also called a DV cable or 'i.Link'..) cable should do.
Buy a cable, start iMovie, connect the camera, put it in VCR or Replay mode, start importing.