I wrote up this tutorial to help beginning to intermediate flash programmers learn how to use data structures. Sounds amazingly boring and nerdy, but if you want to have manageable and, more importantly, working games and whatnot, you're gonna need them.
If you have any questions, feel free to post them in the comments. I will read and try to respond to every comment made, unless I get a flood.
Also, sorry to the audio artists who's awesome songs got butchered by Flash's compression software.