CNN Video & Firefox -- FIXED!
Jeremy,
I had the same problems on a new 20 inch iMac running the latest version of Firefox.
I'm coming from the Linux community (a new convert) and I know how I got it to work there and guess what?? The same fix works with Firefox/Leopard too!
Click on Tools >> Add-ons, then click on the "get extensions" link at the lower right corner of the extensions window.
This will take you to the Mozilla Extensions web site. In the search box there, type in "user agent" (without quotes).
The first hit should be User Agent Switcher. Install that, then restart Firefox.
Go to CNN's site and select a video. When the video begins to play (without video), go to your tools menu and select Tools >> User Agent Switcher >> Netscape 4.8 (Windows Vista).
Refresh your browser screen and the video should play perfectly.
David