Regular readers know I am involved with Jewish Environmental non-profit Hazon. Hazon's signature programs are our bike rides and food work. I recently read of two great iPhone apps that fit our profile wonderfully. (Despite the date these are not April Fools jokes.)
First check out the Locavore iPhone app which I first read about from John Halamka's GeekDoctor blog. This app uses the location finder capability of the phone and then tell you what is in season locally and where to find it.
Secondly, and my personal favorite (as a bladder-limited cyclist), is the iPhone Have2P restroom locator.