I got the SonyEriccson T610 phone which has Bluetooth and I'm using T-mobile service.
I switched from Nextel and I'm very happy.
Since it has Bluetooth built in I can use the phone as a modem without having to physically connect to my laptop and I get about 128K speeds. Also since the phone has Bluetooth all my contacts, calenders, and notes get synced with my laptop my phone so I no longer carry a Palm.
I also got the Hotspot service from T-mobile, $20 a month, so I have WiFi service at Starbucks and many other places.
600 minutes a month, free long distance, nights and weekends free, $39.95
Unlimited Internet on the phone, $19.95
Unlimited WiFi service, $19.95
You can get the phone here with service and make $50.
http://www.hellocalls.com/t610.html