The new iPhone 3G will not work as tethered modem. According to iPhone Atlas, an AT&T rep said, "AT&T will not be supporting a PAM plan for the iPhone 3G. The only
available data plan for the iPhone will be the new $30 consumer
unlimited data aand visual voice mail plan and the $45 business data plan."'
Please note if you are able to tether you iPhone, additional data charges may occur. This kind of tethering has contributed to astronomical cell phone bills in the past, like the Canadian Oil Tester who racked up $85,000 C in data charges.