I paired my T68i mobile phone with my PowerBook today so iSync will auto-sync (via bluetooth) my contacts with the phone, my Mac and my online .Mac account. Neat.
After just replacing my mobile for the 3rd time this year due to me loosing them in taxis, this is a nice feature.
I've been playing with the bluetooth SMS support in OS X which is very nice; one click to send an SMS from a contact in your address book & incoming SMSs popup on the screen. Nice.