Profile Ranking
Design and Skin Customization
First of all, you'll need to know where your profiles are located. The simplest way would be to create a custom form field for the profile update view and get them to enter their location.
Alternatively, checkout the jrGeo module or SteveX's Google maps module to see if they can automatically create a profile location field(s) from the users' IP address.
When you then have a location field, you can then use it in the appropriate jrCore_list function to filter the searches accordingly.