Wow! I’ve been planning making something very similar for a project I have in mind. This is probably going to save me several hours (I hope).
http://www.codeproject.com/aspnet/LatLaysFlat-Part2.asp
The Google Maps API allows you to dynamically display a map from Google Maps , add markers to it(those little windows that pop up showing the address and other bits of information), and assorted other cool things.