How can i resize a quick time movie file?

I really want to upload some of my videos to youtube.com but it says the file is large.. how do i resize quicktime movie (mpeg) files? do i need to use a different program to do so?
Answer
I am assuming you wanna compress the movie (reduce the file size) and not resize the dimensions. if so, the best software to use are autodesk cleaner or sorenson squeeze. you can download trial versions of both at the following url:autodesk cleaner:http://usa.autodesk.com/adsk/servlet/index?id=5562025&siteid=123112sorenson squeeze:http://www.sorensonmedia.com/products/?pageid=2