Which PDA to persue for my business

[rtwpld]

I could really use some help from anyone out there who could offer some input, point me in the right direction or give me someone to contact. I am an intern and am in the beginning stages of developing a system for my Air Conditioning company that would use PDAs to allow our workers to document the repairs they are making on site and wirelessly send the specifications back to the company. This would include a very user friendly drop down menu system of options that detail what is being worked on and what repairs are being made. The menus would each correspond to a number that would generate a code which would allow others to look up that code and quickly see what repairs had been made at a given site. I am working out of the Wilkes-Barre Northeast Pa area and would require at least 15 - 20 handhelds. I need a system that will not become obsolete in the near future or one that is easily upgradable. We are currently running Windows NT and 98 and alot of our documents deal with MS Acess. I was wondering if you could provide me with some input on a PDA to persue that would be the correct avenue for us for these specifications. Thank you - Ryan Watson