What about the "brilliant" casio plug-in for mac QT viewing that is not so brilliant (choppy playback, similar prob with other plug-ins i have tried)?

I work for a Mac using group of people - I want to be able to create manageable size files that any Mac user can see.

Solution:
1) Download and install the ffmpeg converter described in this blog.
http://homepage.mac.com/major4/

2) Then download and install the MPEG4 QT component for OSX from http://www.3ivx.com/download/macos.html

3) Use ffmpeg to convert from AVI to MOV

4) Open your movie (which should play with no problem now that you have your MPEG4 plug-in)

5) Export from MOV to Quicktime.

6) Do the dance of joy!