The message directed the user to contact AT&T to set up the feature. This is consistent with how the iPhone tethering works in the US (a feature which is free in many other markets).
If these rumors actually turn out to be true when iOS6 is released later this year it is probably going to be viewed as another challenge by the Verizon / AT&T duo to the FCC. It appears to be a challenge to even the weaker net neutrality rules that the FCC passed for the wireless carriers.
This is yet another try by carriers to tax services that other companies have innovated and is testament to the inability of carriers to add value to their customers.