action-script/programmer for Geo-Distance Formula Work

Hello Coders i have a working flash map and i am able to plot any city depending on its longitude latitude value correctly on the map. i need to plot circular range rings for given distance from single latitude/longitude value. plz visit the following url at the bottom of the page, where it says "Draw range rings around a point" w w w . g p s v i s u a l i z e r . c o m / c a l c u l a t o r s (remove spaces) it produces a bitmap but i dont need bitmap, i just need latitude/longitude points, using which i can draw range ring within flash. useful resources; [login to view URL] [login to view URL] [login to view URL] coders who have previous experience with Geo-Calculations are ideal candidate for this project. the longitude/latitude points should be with pin point accuracy. thanks