U.K. iPhone carrier O2 has said that it will disconnect any customers found to be using the tethering feature of iPhone OS 3.0 that aren’t signed up for one of the company’s tethering Bolt-On plans. A number of iPhone users who have installed the 3.0 update have reported that it is possible to use the new tethering solution without singing up for the plan. O2 is planning to roll out its tethering Bolt-On plans for the iPhone 3G and iPhone 3GS today with the launch of the 3GS, more information on rates and plans can be found in this article.
O2 warns against unsupported tethering

Charles Starrett
Charles Starrett was a senior editor at iLounge. He's been covering the iPod, iPhone, and iPad since their inception. He has written numerous articles and reviews, and his work has been featured in multiple publications.