http://www.macrumors.com/2008/08/28/apple-and-atandt-discussing-official-tethering-option-for-iphone/
Gizmodo reports on an alleged email Steve Jobs sent to one of their readers. The email was in response to a complaint that AT&T is not offering a tethering option for the iPhone, even though it is offered on other smartphones as a $30/month add-on. The response acknowledged Apple and AT&T were discussing the option:
We agree, and are discussing it with ATT.
Steve
'Tethering' allows users to connect their laptops to the internet by using their mobile phone as the internet connection. The lack of a tethering option for the iPhone was highlighted recently due to the enormous interest in Nullriver's Netshare application which was temporarily available through the App Store.
As mentioned above, AT&T does offer an official tethering option for many of its smartphones as an additional $30/month charge.
http://gizmodo.com/5043218/rumor-apple-and-att-developing-iphone-tethering-plan