Yep! I second Divx!
Go get the free download of the basic encoder, then, go get a free video app like VirtualDub, (virtualdub.org) and in the output settings for encoding, choose and setup your Divx encoding options, just as you would in Premier or After Effects
Should be NICe and small.
An alternative that is hard to beat for file-size savings is to download the free Windows Media Encoding Developer Toolset.
Take your compiled movie from AE, Premier, or VD, and import into the WMVtools app, then tweak away!
Good luck!
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com