AMFPHP
It?s fast, reliable, 100% free and open-source. With this new version we have strived to make a product as stable and full-featured as ColdFusion-based remoting (the reference implementation). You also get to use the wonderful NetConnection debugger, which shows you exactly what's being sent between the client and server. Remoting uses AMF, a very lightweight binary format that cuts the bulk out of packets, meaning data exchange is a lot faster than with XML
