There is a slick app available at the Android Market titled EarthNC. It is described as “seamless charts, user waypoints, and realtime navigation. …features seamless NOAA marine charts for US waters, user waypoints, and realtime navigation.”
I downloaded it and have been playing with it for a couple of weeks (on my Samsung Galaxy S Android phone). I have not used it on the sailboat yet (where I have a Garmin 441 chartplotter) – my use has been just ‘for play’ and on land. That said, it is pretty neat. Having charts at hand all the time has certainly been nice. When a question comes up, I just fire up the app and take a look. Obviously, this is not a life changing ability but certainly fun. 🙂
The Lite version is free. The HD (full) version is $9.99. That’s pretty small price for a case load of charts in your back pocket!