An interesting report that of current iPhone users on AT&T, 26% say they will move to Verizon. Out of all total AT&T subscribers just 16% say they will move to Verizon this year.
Now this was only a poll of 4,000 users and you can question how diverse the group was, but I am guessing these are fair numbers.
Regardless I am very interested to see what actually happens, also keep in mind Verizon still has not announced what the monthly charges for data will be for iPhone users.