Free data tethering programs for the iPhone have been around since it was first jailbroken. I was using MyWi for a while, but due to corporate security issues, I had to lock my phone back down to test Good Messaging as a Lotus Notes app. Being grandfathered into AT&T's unlimited data plan, I've been hesitant to start paying an extra $15 a month for the 4GB data plan with tethering.
But just as I was about to give in to the data caps, iTether suddenly appears in the iTunes app store. Yes, Apple allowed a tethering program into the app store. For $17 (which is less than the cost of MyWi) you can tether your iPhone to a computer via a USB cable.
That's not quite as good as turning your phone into a mobile hotspot, but when you're in the field and have got to get photos from your camera to a computer to the Internet, it will work.
I tested it last night and had no issues with installation or setup.
Sadly, iTether has already disappeared from the app store this morning.