If you are travelling to another city (or country) and need to know about other Facebook friends who may be located in or around that region, check out Map Motive.
Map Motive is a Facebook application that digs through the profiles of all your Facebook Friends to determine their current location and plots the whereabouts neatly on a Google Map.
All Facebook Friends on Google Map
Facebook Friends in a country
Facebook Friends in a region
You can then zoom to a country, city or even street level and know if there are any friends around. If any of your friends have kept their contact information private on Facebook, they obviously won’t show up in the Google Map. Hat tip Keir Clarke.
Update: Map Motive Facebook App is no longer working.