I have a nokia 5500 sport mobile phone, and I found after i installed google map, it can automatically locate to my current position. and I want to know how google map get my position and mark it on the map ? How can I programming implement this feature with symbian C++(nokia 5500 's operate system is Symbian 3rd).
This is one of those questions where you need to know the jargon in order to find the answer. The magic word is "Location API".
Using it, I found this: http://wiki.forum.nokia.com/index.php/Google_Maps_using_Location_Api_in_Symbian
For mobile devices, a location API sometimes more or less hides the details of how the location is actually discovered, and just tells the app where you are. If the phone has GPS, it will use that. Otherwise, the phone network will help it out - it might calculate based on distance and/or direction to one or more base stations, or it might just say "sorry, I can't be very accurate, but I know you're in this cell, so you must be with a few hundred yards of the base station (city cells), or a few of miles of it (rural cells)".
The API used on the page I link to seems to be specifically GPS. Not sure whether it exists on non-GPS handsets, but if you poke around the Symbian docs long enough you can probably find an alternate location API.