I've got my Tungsten T3 paired with my Sony Ericsson T68i. This allows me to send SMS messages from the Palm and connect to the Internet using Bluetotth instead of IR.
I haven't tried to sync the Palm using Bluetooth but as arch13 explains, it's easy enough through the COM ports.
I tried syncing my contacts with my T68i using Sony's XTENDConnect and had miserable results - XP would fail to recognize the phone. I'll have to try arch13's method.
Bluetooth on my T68i was worth it for the BT Jabra headset. No wires has always been the promise of technology and it's a joy to not get tangled when going handsfree.
When it comes to mobile phones and Bluetooth, you'll find them limited by the built-in BT profiles. For example, I cannot "browse" the contents of my T68i because it lacks the necessary BT profile for that function. However, the T600/610 can.
If you're using a Mac, try
Salling Clicker . It allows you to use your Sony BT phone or Palm to remotely control your Mac. iTunes, DVD player, PowerPoint, and more.