You can increase the file size  by following the procedures below:

1. Go into SharePoint Central Administration.
2. Select Windows SharePoint Services in the left menu.
3. Under the Virtual Server Configuration section, select Configure
virtual server settings.
4. Select your portal from the list.
5. Under the Virtual Server Management section, select Virtual server
general settings.
6. Under the maximum  Upload Size section, put in your maximum upload
size.

I've been successful in uploading files that are several hundred MBs.

If you're going to go this route, be sure you are running SP1. RTM had some
serious issues with larger files, which is part of why the limit  is set where it
is...