I only used Smack yesterday to see if it works..., I use Sony's Vegas Movie Studio.
You will notice an Help button on the RAD front page. That takes you to the online "tutorial". Choose "compressing with Smack" and a page telling you how to do it will pop up. Maybe using the Compress to a % of the original is the easiest way . (IE Smack, the original file is 20MB and you want a 2MB file ,choose 10%)
Another way is to use RAD to transcode from .MOV to AVI (Convert a file) then import the AVI into Movie Maker, drag the file to the timeline and use the Save to my Computer option, Movie Setting, Show more choices, best fit to file size..in MB, or Other Settings and pick the compression you want.