T42 is a powerful mobile transit navigation system for the iPhone. It tries to tell you how to get from one point to another in an unfamiliar city by way of an optimal route, taking all different means of public transport into account.
CapCode is a navigation system for sailors with a specialization in regatta assistance. It handles acquisition of data coming from NMEA bus and GPS, computation of the VMG, and route tracing on raster charts. It contains a chart editor.