TorahMom, the Palm Treo and Centro allow you have a phone and your PDA in one. They work like a regular Palm but they also have a phone and camera. And you don’t need a data plan (at least with Sprint). You can even beam or bluetooth all your applications you currently have on your Palm to the Treo/Centro.
(The only difference between the Treo and Centro is that the Treo is a bigger phone (larger screen and keypad) then the Centro.)
The problem is, some of the cell phone companies and pulling the Treo/Centro (including Sprint). For some reason, they are not selling these great phones anymore. If you can get your hands on one, your lucky. But try not to get a used one. Many have the used ones have many problems.