A full .avi movie (in decent quality) will be at around 600 to 700MB.
Expect a full .mpeg movie (if you find one) to e larger than that.
If you see files that are like 350MB, then it could be that it's only a part of a movie.

__________________
iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-