Tungle
"Tungle is a light but powerful peer-to-peer (P2P) meeting coordinator. You can use Tungle to arrange meetings with friends, co-workers or business associates no matter where they are or what calendaring software they use.
"Tungle provides you with a view of the times your friends, co-workers or business associates are free or busy - in advance of sending a meeting invitation."
It's free too
[For other personal productivity tools, see the free and commercial pages of the Directory of E-Learning Tools]
