I was very pleased to find that, with the newer digital phones I can establish connect speeds upwards of 70+Kbps!
It requires making a digital connection over GPRS, and I've been able to do it all over the country and half of Europe so far...
The phone number that is dialed is typically something like *99***1#, and the username is something like ISP@CINGULARGPRS.COM
with a password of CINGULAR1 (all uppercase).
Even with these phones, making a standard dialup call to a regular ISP usually only results in an analog connect speed of about 9.6Kbps.
Even better, with the new Bluetooth capability, you don't need any cables.