I released Mapee Lite. A free show case that demonstrates the map feature of the iPhone OS 3.0. Mapee Lite shows Twitter friends on an iPhone map. The lite version is limited to up to 10 friends on a map.
The experience was great: Flying pins & movable maps using the iPhone MapKit, Twitter API via JSON and Google Map API for Geo-Coding (yes, MapKit does only reverse geo-coding). The twitter profile most likely contains some text describing the location of the user. I need to ask Google what the geo-code for that location text would be (latitude/longitude) and then pin in on the map. I thought it would be simpler.
The pro version of Mapee will be coming out soon. It's basic idea is firstly to show your own tweeps and secondly to discover and follow other tweeps based on location.