There seem to be 2 Chris's in this post, but I'm going to assume you mean me, since it was right after my post.... No, I've done NOTHING to enable this...no ipcc file, nothing. I'm running iTunes 8.2 on a MBP, so installing a custom ipcc isn't possible. Like I said earlier, I honestly don't know if the "Internet Tethering" setting was there on Friday when I got the 3GS, because I assumed AT&T wasn't allowing it yet, so I never checked. But I do know that the MMS toggle wasn't there, because I looked for it Friday.
Well there actually is a way to put an ipcc file on it with iTunes 8.2 ive done it.
But I believe you, and I want to restore so nothing modified is on mine and see if it shows up legitly. I just dont want to take the time to restore :/