Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
A little more specificity would be helpful. What kind of clips? What's the source? What do you need to do to them? What's the target output? iMovie springs to mind, because it comes with every new Mac, but if we don't know what you're trying to DO, it's a lot harder to make an effective recommendation.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.