Somebody reacted on my bit yesterday that cell phones hadn't had that much impact on his life compared to the Internet at large. But on the long run, cell phones will be much bigger than computers. Just look at the numbers. There are half a billion computers in operation and 1.4 billion cell phones in use. Most of the cell phones are simple machines, solely used for well, talking, but that is already changing.
This is where Moore's Law kicks in. Moore predicted in 1965 that the number of number transistors on a chip would double roughly every 18 month. It pretty much has. Doubling the number of transistors you'll get for the same money means that you can either double the capacity of the computer/phone or half the price for the same thing.
In the end it is not the power or the price of a technology that determines the ultimate success. Moores Law will make the thing cheaper and/or more powerful until it is enough for all practical purposes. Inkt-jet printers clearly have reached this point, as have calculators and alarm-clocks, for example. The tech inside doesn't matter. It is powerful and cheap enough. No doubt, both computers and cell phones will get there too.
In the end the cell phone will be the information device of choice for most people. Cell phones will become fully capable internet devices, ready for any form of communication. Already you see that a lot of people that are not very comfortable with their computers, love their phones. In the US and to a lesser extend Europe, people have large houses with enough space for one or more computers. In other countries where people live in tighter quarters, pc usage at home is much lower. One of the reasons why advanced cell phones are doing that much better in Japan and South-Korea.
Internet ready cell phones now cost around 400 euros. That needs to come down a factor 10 or so to make it a feasible option for two billion people. With Moore that will take five years.