Color map is the "skin" of your model, something like this:
(you can see some unfinished areas in the example, that's how that UV mesh looks like before you paint over it). Alpha channel controls specularity of the surface.
Data map is how you tell the game which areas of your texture should reflect environment and how much, which should glow and how much and which should be painted in the color of your team (and how strongly).
It looks like this:
You primarily handle RGB (Red Green Blue) variables to control each aspect; Red controls team coloring, blue controls reflectivity, and green luminosity. In the alpha channel you can also control the amount of bloom associated with your textures.
And finally, the normal map:
Though it looks a bit different when saved as a .dds file, the normal map controls bump mapping on the texture. You generate normal maps by using NVidia's Photoshop plugin... you also need Nvidia's plugin for saving .dds files in Photoshop.
Hope this helped a little!
