An official tethering option for the iPhone is coming "soon", according to AT&T Mobility CEO Ralph De La Vega. The executive confirmed the ongoing rumors in an interview at the Web 2.0 Summit, but did not disclose either a specific timescale or any idea of pricing. Tethering is the process of connecting - either wirelessly or via a cable - your cellphone to a laptop or other mobile device, to take advantage of its mobile internet connection.
It's an ability that Apple and their carrier partners have been careful to restrict since the launch of the original iPhone. An app called NetShare, which allowed users to turn their iPhone into a WiFi-connected modem, was pulled from the AppStore as it contravened the terms and conditions of service. However back in August Steve Jobs was rumored to have contacted at least one customer, telling them that Apple was in talks with AT&T regarding an official tethering option.
One thing is pretty certain, however: the unlimited data access that iPhone users currently enjoy on their handsets will not be carried over to tethered use. Although there's no indication of what conditions will be placed upon the system, it's likely that a fairly strict cap will be implemented to prevent the AT&T network getting bogged down.