Apple Puts Onus On AT&T For 3G Tethering, Confirms Hardware Support

Now you can focus your rage directly at AT&T for the lack of a legit tethering solution. In the Q+A, Apple's Scott Forstall put the onus on the carriers to come up with an official tethering solution (at extra cost, of course):

Q: Where do you stand on tethering?
A: There's two pieces needed to support that: client side and working with carriers. We're absolutely supporting tethering in the client side in iPhone 3.0, but we're working with carriers around the world to see when they can add tethering support on their networks. But we are building that support into iPhone 3.0.

Looks like jailbroken tethering will live on, for now.

[iPhone 3.0 OS Guide: Everything You Need to Know]