T-Mobile USA is apparently about to debut a tethering and Wi-Fi sharing add-on for smartphone users. The plan will be available on November 3, and will run you $14.99 per month. That's less than most other carriers are charging right now, but the data you use will count towards your 5GB cap. To be eligible for the add-on, your must have a 3G phone and a data plan of $19.95 or greater.
It is still unclear how T-Mobile will be implementing the feature. It really sounds like they are only selling you the contractual right to tether, not the means to do so. No official T-Mobile phones come with tethering built in. The upcoming new MyTouch may have an app pre-installed, but that doesn't do much good for other users. "The set-up process will be determined by the type of device customers own and will be different for every manufacturer," reads the leaked document.
The leak also indicates that T-Mobile will be sending a message to people tethering without authorization. Considering many T-Mobile Android users are taking advantage of tethering apps, we aren't sure how they could know who is tethering. It would all look like data to them. Stay tuned for updates on this one folks.