chat proximity

How would one set up drupal to get a rough idea of where users are then put them into a chat room / node (with a communication resource) with other users that are in their area?

This could be done automatically like mentioned above or users could click on a world map to go into a chat room of their choosing, or both.

I would love to get something like this going in the next day or so, if possible, on a basic level. Any help would be appreciated.