The new HP iPAQ 6315 is a Pocket PC Phone Edition with phone, WiFi and Bluetooth! We'll be posting a review of that unit next week. So far, it's been a great device. It's offered by T-Mobile and has just become available in the past few days. You can go with their iPAQ combo plan (combines WiFi service at places like Starbucks) plus 1000 anytime minutes plus unlimited GPRS Internet, or you can go with any other plan you wish. If you don't want their WiFi service, then you could go with a voice plan plus their $20 Unlimited Internet (GPRS).
In addition, you can use an SD WiFi card with many of the Pocket PC phones reviewed on this site. Just check to see if the review says they support SDIO.