Inspect AMF Traffic for Flex
Whenever I develop in Flex, I've always used ServiceCapture. It is a commercial product that inpects all type of traffic including Flex's AMF, a binary format based loosely on the Simple Object Access Protocol (SOAP). ServiceCapture runs about $34 per seat. It allows me to see what traffic is being sent back and forth between my ColdFusion Server and Flex for debugging and QA purposes.
I was made aware today of a new player in town that integrates into FireBug for FireFox. It's currently experimental, but seems to work nicely. Check it out.


Its an integral part of Flash Builder IDE and is very tightly integrated. It has got all the general features and exclusive features including source code navigation.