Came upon this fantastic demo and source code today from Michael VanDaniker.  Over the past few months, ever since Universal Mind launched their Spatial Key application, I have become fascinated with heat maps within Flex applications.   I have been able to find some pretty decent demo's of this type of data visualization but until today, nothing that explained how they work... and not a shred of source code for examination and study.  Michael VanDaniker has a fantastic demo with source and explanation on how Heat Maps work.   Many thanks to him for helping to unlock this previously "mysterious" form of data visualization.  Michael also has a code project and repository on Google Code with some other nifty data visualization components.

Cheers Michael, I owe you a beer or three.