Currently working with Pusher and porting the JavaScript library. This ActionScript version is stable as far as I know, but please let me know if you have troubles. The JavaScript version has been updated a bit and I have not found the time to keep this one 100% in sync with it, but I don't believe the changes are anything that should stop you from using this library.
Also still missing is a demo app which we will likely be keeping as a separate repository that contains a similar demo for all the languages. I may also add some super simple demo code in here at some point.