This is old news for most people, but Apple really messed up with iMovie version 7 (aka. iLife '08). I was trying to put together a simple video with a long stretched sped up and then a 'Ken Burns' image at the end, and no matter where I looked in iMovie I couldn't find the option to speed up the video. Turns out it wasn't even included in that version. Going back to the previous version, iMovie 6 HD, I did find a "speed up" effect, but it was so limited as to be useless to me.
Good thing I know of the old "add and scale" trick in Quicktime. I still needed to edit the video to have the image at the end and some transitions, so I thought I'd do the transitions in iMovie then export to a new file, then fix the speed in Quicktime, then import that back again into iMovie to add the image and music. If this sounds overly complicated, it's because it really was. It wasn't even a workable solution as when I sped up the movie I just had exported from iMovie it ended up dropping so many frames it was unbearable.
So as I was exporting the clip again for the second time in hopes of getting it fixed, I thought I'd try the known route: doing it all in Quicktime. I wouldn't have any fancy effects, but with the estimated time for the export of the new file being about one hour I had time to kill. Quickly opened the files, Motion-JPEG being easy on the processor, trimmed out what I didn't need, pasted together and fixed the speed; then did the Ken Burns image quickly in iMovie, limited to 10 seconds, but ok. Export that while the first was still going, quickly pasted it all together onto the audio track I had prepared.
End result: iMovie taking the better part of two evenings and nothing to show for it but big temporary files; Quicktime Pro got it done in about half an hour. I know it's a matter of what tools you know best, but Apple seriously messed up with iMovie, at least for what I want.
Oh, and the video.