No one has mentioned the Garmin Pilot Android app. Can't speak to how it works on a Galaxy, but kicks butt on a Xoom. $49 a year gets you geo-referenced (follow the airplane on the map) sectionals, low/hi IFR with weather overlays. Includes downloadable approach plates in the main app, and AOPA's (I think) database that pops up the info on the map.
For another $49 a year you can add geo-ref'd approach plates, and for $29 add SafeTaxi (follow the aiplane around the airport diagram).
A cool thing is that the license is good for two devices for these prices. We use the Xoom for primary 'back-up' (snicker nav, and my DroidX Android phone backs up the 'back-up'. The app looks great on the Droid also...very usable.
The main app will do everything we need plus for VFR. They have a one-month free trial subcription, also.
Jim
PS- We use the internal GPS's on both the Xoom and the Droid in our 172 and Citabria with no lost signal so far.