One thing to be aware of is that there is a bit of a hack to start using your iPhone for tethering right now and you don't even need to jailbrake it. I have a couple of thoughts and concerns about this.

First, I haven't read the TOS lately but you're probably breaking the Apple and/or the AT&T regulations you agreed to so, just weigh the consequences if you do decide to do this.

Second, this will be fixed in an update, Apple can't let this continue going on or they could face legal issues with AT&T so don't get used to the functionality.

More importantly though I clearly think AT&T dropped the ball and should have been ready, but if their infrastructure could handle the load there's little reason why they wouldn't offer it right now. If this is the case then consider that you may be ruining the experience for everyone by helping to overload the network and you probably don't want your 3G internet suddenly sucking, do you?

Just my thoughts on the matter.