AT&T axes unlimited data, unveils tethering price
Currently unlimited data plans for existing iPhone and iPad customers are still in effect. However, once contract renewals come up, don't be surprised if you have to wave bye-bye to unlimited data. The press release did not say if the $20 tethering option would be available to those who decide to keep their unlimited data for now, but MacRumors believes tethering won't be available unless you're on the 2 GB "DataPro" plan. Unfortunately, they're probably right. Update: They're right. Tethering is only available as a buy-up from the DataPro plan, and is not an option for grandfathered unlimited-plan users.
The new data plans take effect June 7.