I am thinking of doing some kind of POS software this late fall/ early winter (I am at the very beginning, nothing decided yet, even if I really do it and I know there are already out there a few, but I first of all want to learn something). It would be very simple first and aimed at small restaurants, but first of all it would include a portable device that allows to place orders and bill customers directly at the tables. I thought that the 770 would be a nice device for that purpose with its high resolution screen (despite the fact that the battery will not last an entire day and there is no Nokia battery charger for a spare battery).
My main question for now is what development language to choose for the mobile part of the system, with the primary concern to select one that would allow me to port easily to a new hardware platform should the 770 platform die a sudden death
Does anyone have suggestions or maybe should I consider other hardware/software platforms from the beginning and not bother with the 770 at all?

Thanks, tira.

P.S. I have a POS system for restaurants at home here and it was ill expensive and needs a licence for every device you add(mobile, stationary) and doesn't work that satisfactory (wonder which OS those devices use ). But despite the practical use/gain of such a system is high, since you save time when you really need it. Only the costs are a killer for small enterprises.

If you write the program in C/C++ for the 770, it should be fairly easy to port to any other platform that has GTK+ (Linux, BSD, Windows...).
If you write in C# using mono and GTK# you could even create an executable that works without modification on other platforms.

As for the battery situation, the best bet would be to have two 770's. One on charge while the other is in use. That would also leave you a backup 770 in case of hardware failure.

As for other platforms, you could write a Java app for a Palm or Windows Mobile based PDA. I would suggest Java, as opposed to their native API's for portability reasons. However, a Palm or Windows Mobile based PDA with WiFi and a decent screen would probably be more expensive than the 770.