I asked this question on Quora and got a really good answer (read here). What I actually had to learn was how to get Flash communicating with PHP using serialization (compared to get/post requests and xml). There are two options for doing this, AMFPHP and ZendAMF. The video tutorials below are a great walk through:
- Introduction to AMFPHP: Part 1
- Introduction to AMFPHP: Part 2
- Introduction to ZendAMF