This is a very useful tool for AS3 and loading data, images, XML, and more! If your already using GreenSock for timeLine most notably tweenMax you’ll understand that these set of classes are very well written. I suggest checking this out and spending the time to watch these videos. All in all there are about 10 with each video being 3 minutes or so long.
For more on this, check out GreenSock website : http://www.greensock.com/loadermax-video/