I might be wrong, but I think only Quick Time Video actually buffers while you download. Thus it basically streams. As previously posted, with gmail you would have to download the whole video before you watch it with the 10mb limit its basically useless with what you want to do.
ourmedia.org does exactly what you want, plus its free!
Another possible (but temporary) solution is to upload a file to
yousendit.com browse to the hosted link that you email to yourself and download your video. But unless its Q-Time you will have to download the whole video before your watch it. I might add that I really like yousendit.com because you can send up to 1GB file to someone... try doing that with email!