German location-based application Plazes has begun a closed beta of a mobile client for Symbian S60 devices, which includes Nokia N90, N70, 6680, 6681/6682, 6670, 3230, 6620, 6630, 6260, 7610. The service, which maps your location based on network presence, allows you to see who is nearby, where you or they have been (what are called trazes), and geotag Flickr images of locations as well.
Last year I had an interesting experience with Plazes on board an SAS flight to Copenhagen, while using in-flight Wi-Fi. I manually entered my latitude and longitude incorrectly to set my plaze, and am now perpetually shown as having visited Kazakhstan instead of being over the mid-Atlantic.
Justin has more coverage here at mopocket.