If you're a student then www.studentfilms.com is a great place to post your films, however they do require a bit of money first.
There's probably plenty of other places where you can host it for free.

For free posting, try:

http://www.youtube.com

or

http://www.ourmedia.org/

Hope this helps.

Dan Rahmel
Author: "Nuts and Bolts Filmmaking"
Free scripts, templates, film glossary, and know-how,
check out: http://www.cvisual.com

Myspace Film is a good one because you can put up a whole profile and photos and so on with it, there are also a lot of sites like 3btv.com who select films to have on their site, some are quite stringent like Atom Films others are more open door like thefilmlink or thelinktv

Steve Piper
Coffee Films
www.coffeefilms.com
www.myspace.com/coffeefilms