How do you program a gps transmitter to send coordinates in real time to someone a few kilometers away?

Am trying to do a project, real time tracking of athletes using GPS, but i have a problem with the communication part between the transmitter and the receiver. Was told GSM can be used but i dont know how, Any other method???? and how do they work. Websites will be greatly appreciated.|||A GSM data module is just a mobile phone with a data port. Feed data into it and get the data out at another phone or a PC.