Starling is a 2D framework for developers who wish to leverage Stage3D (and GPU accelerated rendering) for game development. Starling is an opensource project released under the BSD License, so if you want to contribute or add a feature then feel free to join in.
Articles
To help you get started with Starling here are a selection of articles that you may find of use.
Screencasts
Below are a selection of screencasts to help you get up to speed with Starling if you prefer to learn through video as opposed to reading articles.