Free42 is a complete re-implementation of the HP-42S calculator and the HP-82240 printer. Free42 was written from scratch, without using any HP code. You do not need any ROM images in order to use it, yet it is fully HP-42S compatible
C4Me - The best ROM calculator replacement.
The C4Me is a new generation calculator for the PalmOS with the following features:
Multi-line edit field with standard text editor convenience (large expressions up to 256 symbols).
With the multiple edit fields you can work with several problems simultaneously
SnapCalc is a HackMaster plug-in that allows you to pop up a basic calculator from within any PalmOSŪ application, do some calculations, and, if you choose, copy the result to the underlying application