I'm no expert, but according to George Hotz, the original iphone unlocker, the chip that does the 3G on the new iphone migh also support CDMA, which, if they ever unlock it, could potentially mean it could work on the verizon network.
I guess depending on which chip it is, there could be several modes available, one of which could be the CDMA that verizon uses, which would mean that they could write some software to enable that portion of the chip to work. It's probably a long shot as it would take some serious skills from someone who really wanted to see it work, but it *could* be possible someday, assuming it uses the amplifier chip that George was thinking of.
I don't think they know for sure yet either way, but he first mentioned it here on his blog:
http://iphonejtag.blogspot.com/2008/07/on-unlocking.html.