Is anyone using tethering yet?

With all the demand for tethering in the years/months/weeks leading up to tethering being officially available in the U.S. on AT&T, I'm surprised there's not more info available now about experiences using it, how to get it, etc. (Guess the $20 extra fee really IS that much of a buzzkill?)

Anyway, has anyone been able to successfully activate tethering (especially with iPhone 3G/3GS)? It's not showing up as an option in the AT&T MyWireless app or on the online account management system so I don't have it yet. I even heard one rumor (don't remember the source) saying that iPhone tethering in the US would be limited to just the iPhone 4 despite being supported in iOS 4 on the 3G/3GS - though while that seems unlikely, I have to wonder as it doesn't even yet seem to be an "official" option in that I can't find any mention of it on AT&T's website or account control panel for my 3GS.

For those who DO have it (does it take a phone call or stop at an AT&T retail location) how is it working?