If there is a higher price then I believe it will be subsidized. If that's the case, then say they lop off $200 to give a $499 iPhone price and then you give them a two year contract. To make that cost up (and then some), AT&T jacks up their data rates in line with the competition, so then you're looking at roughly $79.99 per month minimum instead of the $59.99 minimum.
I can deal with the subsidized phone, but what would really hurt is if the data plans go up to compensate for the phone discount. I currently have just a $39 per month plan. I can stomach another $20 a month, but another $40 would be a hard price to swallow. That's $1,920 on top of the $499 you spent.
What has attracted me most about the iPhone is the interface, features and the fact that AT&T (US) had the cheapest data plan. I hope that AT&T doesn't become charge happy with the latest release next week. They've had one LARGE capital expenditure to get 3G capability across the major cities in the US, so it will be interesting to see if they introduce some additional fees/charges and how that will affect customers coming on board.
I do believe the iPhone price will be higher due to what additional hardware & software features are being included in this version. An additional camera, 3G, GPS, video conferencing, larger hard drive (32GB) plus Apps Store later this month.