yes as far as ican see
I imported a clip I took yesterday (it is on my flckr site also) only 11 seconds .
The original was at 30fps PAL and I had iMovie set up for 25fps PAL (as default) and it asked if I wanted it changed to 30 as per original and did so without any problem
not sure about NTSC but I see no reason to think it would be different
the one on flickr was straight from camera to flickr I never modified it at all as it was simply a test for sound in a quiet environment
hope this helps