This link, which I originally got from
woofiegrrl, will let you save videos from sites like YouTube. I've used it a lot; and I'm seeing more and more people passing around YouTube links, so I figure some of you might want to use it, too.
EDIT: I've been using this thing for weeks without ever a problem; but now that I post the URL, it doesn't seem to be working. Maybe it's just maxed out on bandwidth, and will be back later?