GSM vs CDMA
I agree with those who say Apple will need to release a CDMA version of this phone, at least in North America where CDMA has a leading market share. (This assumes, of course, that they will be making this phone available to work with other carriers' networks, and not asking consumers to switch to an Apple-branded MVNO network).
Beyond market share an additional reason, in the US and Canada, is the availability of much higher-speed data networks from the CDMA providers ... Verizon, Sprint, Bell, Telus. Remember that Jobs & Co. are not averse to pushing the envelope when it comes to getting people to adopt newer technologies. They did it with floppy disks. They recently did it with modems. It would be entirely consistent for them to roll out this phone with data services (tied to .mac) that benefit greatly from being on the fastest possible networks.
In Europe, Asia and elsewhere the situation may be different ... 3G and more evolved EDGE networks may be in place ... but in North America, if you're interested in mobile data coverage your best bets are WiFi hotspots and EVDO CDMA networks. That's likely to matter to Apple.
Certainly they're likely to offer a GSM version as well ... Apple markets worldwide ... but I don't see them locking themselves down to GSM providers any more than Motorola does.
Finally, as to pricing and whether Apple will sell unlocked versions apart from the carriers ... remember, it's not just a phone! It's probably an iPod and a PDA as well. Unless you win a raffle, you don't get either of those free these days ... people already pay a lot of money for them, and some people, including me, would gladly pay not to have to carry two or three of those devices.
I wouldn't be surprised if I could walk into my local Apple store (in the US) and ask for one of three models: CDMA-A, CDMA-B, or GSM quad band. That would cover all of the carriers except Nextel. You can get an unlocked quad-band GSM phone to be recognized by a network by plugging in a SIM, and the CDMA networks will similarly allow you to register a compatible phone with them, wherever you got it. Moreover, you might be able to switch among those carriers by merely buying and changing a removable chipset ... allowing consumers to pick the providers and plans they want.