Networking & wireless: Exporting XML file continously

Exporting XML file continously

Hi
I'm using crossbow MTS420 sensor board which contains GPS . I want to make a mapping software to show the location on a map . In order to do that I need to export an XML file which contain GPS data and use this file in my mapping software . My problem is that I need to generate this XML file automatically . I know how to generate XML file in The GUI that I use to show data ( Moteview ) , but it is manually . I need to generate XML file automatically for each reading so the data will be shown in mapping software in real time . What do I need to do this ? , plz help if you can .
Thnx