CS3 can save the .fla as Flash 8, and F8 can open it without problem. The
only thing is that you can't just do a 'Save' in CS3 - or you get a warning
saying 'the document will be upgraded, blah blah blah', you have to actually
do a 'Save As' to save down to 8. So, you can't just CTRL-S, or you get the
warning, but otherwise there's no issue.

--
Dave -
Head Developer
http://www.blurredistinction.com
Adobe Community Expert
http://www.adobe.com/communities/experts/

All our staff currently use Flash 8 Pro. We have a new GA starting Monday, his
computer arrived today. But, we received CS3 Pro instead of 8 Pro.

I?ve searched the forums and have found posts that hint at 8 and CS3 being
able to work on the same FLA files, but I need to know if in fact our
developers using 8 and our new hire will all be able to work on the same
projects using the same FLA files.

I have to decide to either send back the copy of CS3 Pro and get 8 Pro for the
new hire or upgrade everyone else to CS3 (and justify the expenditure).

Any facts would be greatly appreciated.