I've never used the program 'Movie Edit Pro ' but I'm sure it's like any other program,
under the export (or save as) area, you will have a section or button that says "codec" or "compression" or something similar. In there you can choose different codecs. All i know for certain is that sound really adds a lot to the file size. You could change the codec for the sound as well to something smaller, (although i haven't played enough with sound codecs, i'm going to assume there's an mp3 codec or somesort that's handy and small

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I know Windows XP has a native program called "windows movie maker" it can make ".wmv" format, and it has preset's setup for different mediums, like dvd, web, or HD, stuff like that.
I found that divx codec works really quite well. along with quicktimes H.264. I also used the sorenson codec in the past, but it really doesn't compare to the H.264 codec ( but is still a solid codec.)
I'm not the most knowledgeable in this area, and I'm sure there's others that can share more light on the subject.