There's also a decent compass app and another that gives speed, position, and angle of heel (can't remember the name of the app!).
It's called Spyglass, with a junior version called Command Compass
. Great app on iPhone. Want to get the Android version for my tablet.
Ship Finder Free is a cool AIS app I have on iPhone.
Polar Navy is a great app on a netbook, or laptop. Tried it on iPhone and it was horrible at first, but I just loaded it up again, and it must have come to its senses and looks great. Probably will get it onto the tablet one of these days.