In fact, you can. The function is called dial-up networking (DUN), and your Treo has it. You just can´t see it. Instead, when you click on your phone´s Bluetooth screen, you get the screen at right, without DUN. Why? Sprint says it´s because PalmOne, the Treo´s manufacturer, did not have the correct DUN drivers when the Treo launched. Cingular says the same thing.