The 3.0 version of the OS, coming in June, allows tethering, but it's up to the carriers to allow it. I'd imagine that they'll want a ton of money to allow tethering. But you never know. Actually, the 3.0 OS has a ton of really cool new things in it.
Also, the other day, I was walking to work and bought a song and listened to it in the space of, like, 60 seconds. If you told me 10 years ago that I'd be buying and listening to music on my phone while walking to class, I'd have rolled my eyes. The iPhone continues to wow me.