I just love my Canon 5D Mark II camera that I bought a few months ago. But there are issues with the footage being jerky when using IMovie 09. I haven’t quite had the time to jump into using Final Cut yet, so until then you can use a free program called MPEG Streamclip to fix the video stuttering.
There’s a great article here that will explain exactly what do to:
http://thedigitalstory.com/2009/04/managing_canon_5d_ma.html