I have a clip that I need to start off at a normal speed, then speed up, and then go back to its normal speed. I know FCP is not too great to do this in because the frames get all messed up. How do I use motion to do this to one clip?
It's at the bottom of the Properties tab. Change the timing from constant to variable, then you can control the rate that the video plays at via keyframes. (Meaning, pick when one frame will play, then pick when another frame will play and Motion will figure out when the play all the frames in between.)
I don't know if you're using FCP7 or FCPX, but in my opinion, retiming is much easier in FCPX than it is in Motion. But Motion is easier than FCP7 (in my opinion.)