Find closest location?

Hi-

I have several "search" locations (either address and/or lat/long) from a cfquery.

and

I have one "main" location.

I need to pass all of the values - the "search" and the "main" - into a service (any free service) that will tell me the one closest "search" value to the "main" value. I can specify a radius if needed (200 km).

Anyone done this with CF before? I know there are several Google services that use its Map API but none seem to do what I need....

Thanks,

Rich