Mac OS X 10.6 Snow Leopard does indeed have some "refinements and enhancements" for the iPhone, namely a brand spanking new iPhone logo in System Preferences > Network when you're tethered via the iPhone.
Yeah, okay, we know -- AT&T users need do nothing but raise their fists and yell out a "KAAAAAAHHHHHHNNNN!" like scream at the gaping lack of functionality they're still enduring. But at least you can take the smallest, most infinitesimal comforts in knowing that -- if you're a Mac -- you'll get a spiffy new icon to go with your no doubt exorbitantly overcharged tethering option.
If it ever becomes available.