So if you are using a jail broken iPhone on the AT&T service and you decided to tether well you are in for a big surprised. Your plan will change without your consent. I was just informed that as of Thursday August 11th 2011, if you use MyWi or any tethering on the phone or using the phone as a modem, AT&T will automatically change your unlimited plan to a 2Gb tethering plan for 45 dollars without the customers consent. This is for those who received emails or texts about the use of tethering without an AT&T tethering plan.
This has been confirmed with AT&T. So for those out there that tether and use a jailbroken phone to do so please becareful, you might lose your unlimited data plan and who really wants that?