Slashdot has a good newsbit and discussion over the possibility of smart phones replacing PDAs.
I think this is likely. If I can get a phone to replace my PDA, I will go for it in a minute. Why carry two devices when I could just carry one?
The Slashdot conspiracy group has a good time with this one–“I will never put my information on a device that can be spied on by the outside world every time I make a phone call!”