Where My Friends Be
Where My Friends Be is a nice Google Maps app to visualise the locations of all your Facebook friends. To create a map you just need to connect your Facebook account and in a matter of seconds you are presented with a Google Map showing the geographical distribution of your social network.
Friends Density on Facebook
Friends Density is another nice way to visualise the geographical distribution of your Facebook friends, this time in the form of a heatmap.
Once you sign up to the app in Facebook you can view your friends on a Google Map. You can even read your friends' latest status updates directly from the map.