So, there always ends up being a "Directory" on the forums, but those never really work out, either its not easy to navigate (because its a huge list of cities and countries), or its not kept up because the original poster gets lazy.
So my suggestion is a google powered member map.
Simple as adding a membermap input box in your control panel, and on the registration form. Members put in their city, and state, or select them from drop down menus, then using google maps API, you automatically add them to the map. Of course, its not a required field, and also has a checkbox for hiding yourself.
Here is an article I found about it, I have faith in trash80's skills, so i doubt he would actually need to read this, but in case he wants something to build off of, here it is.
http://idratherbewriting.com/2007/02/08 ogle-maps/
I'll be doing more research on member maps, and I will add any resources I find later on.