"Jaiku is a social phonebook that displays real time presence and location of your contacts. Seems interesting enough. Once installed Jaiku connects to its server in order to display your presence.
Jaiku is currently available for the following S60 2nd edition devices:
Nokia 6260, 6600, 6620, 6630, 6670, 6680, 6681, 6682, 7610 and N70. I was brave enough to install it and get it working on the Nokia N90."