Information on Using PDA’s for Productivity

Just curious… but is there a site on the internet that actually evaluates PDA’s in terms of their original intent – productivity?

I have looked around and there is a lot of information on the additional entertainment doo-dah’s, but nothing about the 11 fundamentals that are addressed here in 2Time.

I imagine that there is room for a product that is actually built around the way people capture time demands and then manage them.

Let me know if there is such a site, or if there is a PDA that is being designed in this way.