YOU MUST HAVE A PUBNUB ACCOUNT TO USE THE API.
PubNub 3.3.1 Real-time Cloud Push API - AS3 and Flex
PubNub is a blazingly fast cloud-hosted messaging service for building real-time web and mobile apps. Hundreds of apps and thousands of developers rely on PubNub for delivering human-perceptive real-time experiences that scale to millions of users worldwide. PubNub delivers the infrastructure needed to build amazing MMO games, social apps, business collaborative solutions, and more.
Checkout 3.3.1/PubNubAS3Example and PubNubFlexExample and the tests for information and examples on how to use!