I’ve been looking at the Bing Maps 8 library. There are some very short but very good examples in the documentation. The only way I learn technology is to actually try it. My strategy for Bing Maps is to take a couple of the small examples in the documentation, combine them, and modify them.
Bing Maps 8 has a pretty nice built-in heat maps module. My demo Web page loads a map centered about Portland, OR and then generates a few thousand random locations in the map view, and then generates a heat map that shows the density of the random locations.
Because the points were uniform-randomly generated, the density is relatively even so the resulting heat map is a bit messy, but my demo does capture most of the essential techniques, including a program-defined color gradient used by the heat map. I followed up by creating a slightly more realistic Web page that loads U.S. city data from a text file and then displays that data as a heat map.