This Sample Application shows how you can tie your own custom data to the map.  In this example we use sales statisctics and tie them to the various census tracts of Austin Texas.  We then setup class break renderers on the sales statistics to render the color of each tract based upon how many sales occurred within it.

To try this sample out click on the first row of the Custom Sales Data (Tract # 001766) and change the sales number from 12 to 99.  After you hit update you will notice that the furthest north tract has been updated with the new value and rendered in dark green signifying high sales.  You can continue to change sales data for different tracts and watch the map be updated automatically.