Where can I get movies...legally

I’m trying to do some development work on Flash videos but at the moment I don’t have any movies to convert to FLV. They’re on the way but I would like to have a system in place for when they get here.

Anyone know where I can download some movie files (avi, mpeg, whatever is fine).

They need to be legal, for free and short though. Music videos or movie trailers would be ideal. I just need to find a site that lets you download movies to your machine. YouTube and Others stick them in your player without a download option.

Any ideas?