We may be a bit late for poppamac but while we're at it... ;)
there are software that will recompress only the end credits (or whatever part you tell them to do) so that they take less space... while you don't kill the quality of the whole movie. It is said you can gain some 15 to 40 MB
these software are supposed to do that easily (I didn't test them)
I know two of them in french (at least the web pages are exclusively in french)
curvavi:
http://www.cheznoo.net/radioatlantique/perso/index.htm
reducteur:
http://reducteur.free.fr/
I'd bet there are some equivalent software in english...