Older movies just aren't as popular as newer movies, so they will be harder to find. With newer movies, you can find almost anything. With older movies, you have to pick what you like from what's available. You can always try torrent websites. The newest (beta) version of Limewire can download torrent files.

Hope this helps

Dan

P.S. Try searching for divx, xvid, dvdrip, movie, etc.