Hi,
I've been writing and mixing music on my computer since the days of the Amiga computer. It's just a hobby - for my own "amazement". Recently, I've become interested in video, prompted by a Christmas gift from my wife - A Panasonic PV-DV53.
Now I'm putting the two together - generating music tracks with one hobby and recording them with video on the other.
I've used a program called Band In A Box (www.pgmusic.com) for a number of years. It can generate songs for you, either from scratch or from chord progressions that you enter. It comes in handy to generate unique music to use with your videos. It's fairly easy to learn and not too expensive - less than $100. There are other programs like this out there. By generating my music tracks this way I don't have anything to worry about with regard to copyrights!
Jim