Unfortunately, you get what you pay for. Yes, there are free programs, but I doubt they will be much better than Movie Maker. Take a look here:

http://www.download.com/3120-20_4-0.html?tg=dl-20&qt=video%20editor&tag=srch

Keep in mind that some of these are just trials.

If editing is something you're going to spend large amounts of time doing, it worth it to buy an editor. I use Ulead Videostudio 10+.