Hi do you want a algorithm to find shortest parth between two points? Or you want to draw in you map or something.? Please clarify what exactly you want.
If you want algorithm then try this
http://en.wikipedia.org/wiki/Dijkstra%27s_algorithm[
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And If you have your algorithm then you need to store the different verticies (i mean places or city or state or country) and edges with their weight (i.e. distance between two different places) Then you can apply that algorithm to you map.
If want some specific info please elaborate it further.