Re: BRAWL 2012
You'll have to use some sort of compression. Your editing software probably gives you a selection of codecs with some quality settings that can be lowered to give you smaller file sizes. You'll likely need to adjust them through trial and error until the film is under the limit.
If I were Goliathan (I'm not, of course) I would amend the rules to allow members to upload unlisted Youtube videos and email the link instead of an entire file, since most people here use Youtube anyway. I don't know how he feels about that idea, though.
EDIT: Disregard my bumbling; you can upload to Youtube.