I wrote a data collection system for out plant floor using the PC tablet from Viewsonic (no keyboard touch screen only). One thing I found helpful other than making the buttons and fields BIG (like everyone has suggested) was to create a electronic number pad and electronic keyboard. The screen keyboard that came with the system was too small for fingers.

After creating the number pad and keyboard I set the getfocus() on all the fields to either activate the number pad or keyboard based on what type of data the user would enter. We have been using it for several months now (9 users for one system, 3 on another similar system) and the plant floor operators really like it.

Alan Wyne
IS Manager
Rollpak corp