WHHHOOOOHHOOO!!! Finally!! some good news about the iPhone! Cause I have recently been frustrated with my the purchase of my new iPhone. Its been slow (but that could be due to many apps I have installed? not sure...maybe time for a fresh start, aka format) and some crashes here and there.
But tethering!? That would be fantastic! TY att!
TechCrunch reports that AT&T-sanctioned 3G tethering is on the way for iPhones "soon." It's good news for iPhone owners, but if soon isn't early enough, you can try solutions like previously mentioned iPhone Modem or my personal favorite, PdaNet.

I was talking on my iPhone with a friend and then after I hung up they could not hear me any more!!! WHAT GIVES APPLE!?!?
Okay, don't panic. Take a deep breath and keep reading. There is a solution and its very simple!
If you some how are stuck with your phone not letting you talk to people, its due to a problem of the iPhone not recognizing that you unplugged your headphones that have the built in microphone. This usually happends to me when I unplug the headphones too fast.
Verify the problem
To make sure that your suck in this mode after you have unplugged your headphones, adjust the volume with the buttons on the side. If you see the visual indicator appear with the title of "heaphones" and your headphones are not plugged in, then the iPhone did not recognize you have unplugged your headphones.
To Fix the problem
Plug in your headphones. Then SLOWLY unplug your headphones
Verify Fix of the problem
Adjust the volume without the headphones in the iPhone jack. If you see the visual indicator appear with the title of "ringer" or "speaker" (depending on your model) then you are in good shape and people will hear you.