Help?! PDA to use as booking diary for driving instructor

Hi, am really clueless to all this so any help or advice would be much appreciated.
Im currently searching for a system/software which will allow me to ,when i receive calls from people wanting to book driving lessons with our school, be able to input this to my pc/laptop at home which would then update to a PDA or something in the insructors car, and vice versa if they take a direct booking from a pupil for it to show on my system automatically?
Is there such a thing?

What sort of PDA would i need for this purpose?

As i say, any advice would be great.
Thanks very much

Nora x

[getsurfers]

Nearly all PDA's have a calendar function. Windows mobile based devices like the HP 214 come with a pocket version of Outlook. You can the sync this with a PC.

HP 214 - http://www.totalpda.co.uk/HP/HP-iPAQ-214.6975.html