It’s a somewhat frustrating situation for U.S. iPhone owners: AT&T, the official U.S. iPhone carrier, doesn’t offer iPhone tethering as of March 2010, but iPhone owners in many other countries have the feature. So, what’s the problem?
It seems to be one of bandwidth. AT&T has famously had difficulty meetings the demands data-heavy iPhone users place on its network. Allowing iPhone tethering – even at an extra monthly fee – would greatly increase bandwidth needs, needs AT&T can’t meet right now.
As of now, it’s unclear when this situation will change. It doesn’t look like it will be any time soon, though, given that Steve Jobs himself has said that the iPad won’t support iPhone tethering.
In the meantime, there is one way to get tethering on your iPhone: jailbreaking. Jailbroken iPhones can support tethering apps on various carriers. But, as the warning always goes with jailbreaking, make absolutely sure you know what you’re doing or you may end up with a non-functional iPhone.