Hi, petey218,
Possibly the footage was recorded in Long Play instead of Standard Play and that might have influenced the import result. Or, possibly you are importing slower frame rate footage into a faster frame rate project?
In any event, try putting the footage into an iMovie project timeline and slowing down the speed. You can do this by Control-clicking on the clip in the timeline and selecting Show Speed Editor from the pop up menu. That will cause a speed adjustment handle to appear in the top right corner of the clip. Slide the handle to the right to slow down the clip, and to the left to speed up the clip. After adjusting the speed, you can then export it as a movie file that has the correct speed.
Another way is to select the clip in the timeline and click on the speed icon (the one that looks like a clock dial) in the timeline at the top right of the project screen. The speed controls will then appear that allows one to slow down or speed up the clip.
-- Rich