As far as I know that doesn’t exist (maybe gpress? not sure…). I implemented that for a couple of my sites, though. It’s fairly easy, but there’s some coding involved.
First you specify a profile field, like Location. Then when someone signs up, or when someone edits his/her profile, you request the geocoded location based on that profile field from Google. Then it’s a good idea to check if that location already exists in the database. Google maps don’t display 2 pins for the same location, so you just add like 0.0001 to both the longitude and the latitude and check again until you end up with a unique location. Then save the location as usermeta.
The second step is to put all of these markers onto a Google map. It’s best to use a script like markerclusterer.js. Imagine you have 10.000 users. When you want to display all of them on one map it’ll take ages to render all of these pins. markerclusterer groups pins that sit in a certain radius together and only displays them when you zoom into the map. So then you pull all the locations from the database and pass it to the google maps script.
Have a look at http://scubavagabonds.com/divers/. I had been thinking of turning that into a plugin (I still might at some point), but for now I just don’t have the time. There’s a lot of documentation available for Google maps version 3 and if you know some php it shouldn’t be too hard.
gPress is a very good plugin, but it does not work, because no menue options in the admin panel are clickable. I dont know why…?
@travel-junkie
Love the “Powered by…” in the footer – cool site!
@pcwriter
Cheers! Many many hours of coding. Even longer to come up with that “Powered by…” line 
