AT&T is offering a discount in the US of $20 off the monthly subscription cost to iPhone customers who abandon EDGE support on the company's mobile network.

The cut comes at a price: losing EDGE support in the iPhone also means users forfeit the iPhone's much-vaunted visual voicemail, as well as being unable to access any websites or email in the absence of a WiFi connection.

AT&T is allowing iPhone users to access their account on AT&T Wireless in order to remove Unlimited Data from their list of supported services.

The move comes as UK users rejoice in O2's recent decision to remove all limitations on data usage on its iPhone tariff - a move suggested by Apple in response to user confusion.

However, early iPhone adopters on the £35/month tariff are already reaching the limit of their paltry 200 included minutes of voice calls, and wondering just how quickly O2's call charges will stack up once those minutes are used up.