Download this, follow the instructions (simple drag and drop really) and find wherever you put the demuxed files, there should be one with a ..m1v extention and a .m1a extension, first one's video and the latter's audio.
I think iMovie will be able to import these, if not then you can count on me screwing around with it until it does.
bbDemux is pretty buggy and it'll probably lock up occasionally but it's the best tool I've found for this.
from what I understand, if you have quicktime pro you can convert them into DV stream format, place them in the projects folder (or whatever its called) and it should work.
But when you try to export MPEG files with Quicktime, you lose the audio (flaw in the MPEG codec) which is why you must demux them with that tool or another.
i tried bbdemux and tried importing into imovie. imovie allowed me to select the files for importing but when i tried it said that it could not open the file. i did this twice with bbdemux with two different .mpg files