Website

Buy TouchRPN on iTunes

Built in Documentation

TouchRPN Tips and Tricks : List of tips and tricks for how to use the calculator

MP-FORTH in TouchRPN: How and where to use it, once you've learned it.

Skins: “Skinning” TouchRPN

MP-FORTH Reference : Language reference for MP-FORTH

MP-FORTH Code : Objective-C Code for MP-FORTH

KeyRPN : Beta (open source, for now) app for the desktop, implementing MP-FORTH. Good place to learn MP-FORTH before writing stuff for the TouchRPN