One of the things that has many iPhone users angered is that while the iPhone has tethering capability, AT&T has blocked the feature. I can only imagine how angry the users would be if they had been able to tether the iPhone for years and the feature was cancelled without notice. Sprint has done just that for some of its customers.
A poster going by kevinapg has posted at the Sprint Blogs that the ability to tether his Blackberry handset has been blocked. The poster states that for years tethering has been supported through the Sprint Smartview software.