CDoF is a depth of field calculator for the Palm OS. It is based loosely on PDoF but with an improved interface, aimed at allowing the photographer to determined the depth of field as quickly as possible, without having to constantly edit the parameters with graffiti.You can always find the latest version of CDoF at the project page on sourceforge.
I'm hoping to add more features to CDoF, but I'm not sure what would be useful. If there are any photography related calculations that you feel would be useful, please let me know via email. Try to include in your email the reason why you feel the calculation would be useful to a photographer, and if possible the details of the formula.
Another thing you can do is to donate. I don't really need the money, but I feel that sourceforge should get something for hosting this project. 100% of whatever you donate will be automatically channeled to sourceforge.