Sorenson 3 video compression is among the best current CODEC for saving iMovies onto CDROM. With the following settings you can squeeze about 60 mins of video on a single CD. You can save your videos to Sorenson as follows:

1. From your iMovie project, choose "Export Movie" from the File menu. From the Export menu (default says "To Camera") choose "To QuickTime" and in the QuickTime Formats menu choose "Expert." (Congratulations, you're an expert!) Name your file appropriately and save it to the location of your choice.
2. In the Expert QuickTime Settings window, in the Image Settings box, give your movie the following sizes: Width = 320; Height = 240. This is half of the normal resolution for TV and normal for CD products that will be played through web browsers.
3. Hit the "Settings" button and in the Compressor Setting window create the following settings: from the Compressor menu choose Sorenson Video 3; slide the Quality bar to Best; in the Motion box, choose 15 frames per second, key frame every 90 frames; leave the limit data rate blank.
4. Hit "OK"
5. In the Expert QuickTime Settings window, in the Audio Settings box, choose "IMA 4:1." Hit "OK" and export your movie to the location of your choice.
6. You can now use your CD authoring software to burn the QuickTime file of your movie onto a CD.   A nice technique to use to make your videos bigger is to enlarge them when you open them in a QuickTime player and, if you have QuickTime Pro, save the video in the new size.  Without adding data to your file, this step will make your movie look bigger when it plays back.