OpenCPN is a free software (GPLv2) project to create a concise chartplotter and navigation software for use as an underway or planning tool. OpenCPN is developed by a team of active sailors using real world conditions for program testing and refinement.
QLandkarte GT is the ultimate outdoor aficionado's tool. It supports GPS maps in GeoTiff format as well as Garmin's img vector map format. Additionally, it is the PC-side front end to QLandkarte M (see next), a moving map application for mobile devices.
Kartendarstellung Seewetter: Vorhersage, Wassertemp
AOL Openstreetmap Web Application
There are many ways of writing coordinates, and converting between the different ways is non-obvious but also quite trivial.