radiusIM combines IM with location. It’s the only site that shows you where your friends are hanging out and lets you surf for other people based on location. It supports all the major networks: MSN, AIM/ICQ, Yahoo, and GTalk/Jabber. And you can use radiusIM from anywhere because there are no downloads.
Log in to radiusIM and choose your location. Your friends will show up in the Friends List to the right and as pictures inside the map. The pictures around the map are other people located somewhere within the map view, but you don’t know exactly where. You can drag or zoom the map to a new place to see new people from that area. Remember that radiusIM is a full application living inside your browser so try right clicking and sizing the windows to make it work better for you.
It uses Ajax heavily, and is built on the Dojo Toolkit.