THere is a good post somewhere with great example - wait let me see if I can find it....
Advanced Wars Grid Movement Look on page 2 for great tilemap example with tile co-ordinates.
Damn, new forum mest with my bookmark system and can't find the one I was thinking of. But it's a father and son who making a game and they gave a little capx on movement and tilemap. Search grid / tilemap and go through all the results - its got to be in there somewhere
Still can't find it - here is an opens source project I was following but got shelved... it was implementing AI Cohack