Same here-just got a Galaxy Ace-my first smart phone.
So far UK charting programme-£15 but access to full uk chart catalogue and it works like any other mapping GPS.
Download charts you need when linked into home wifi and expect a big battery drain.
Tidal prediction app-same as mdr.co.nz world tides.
Traveline scotland which is great when you need to catch a bus or train to and from boat.
Also downloaded a sunrise/sunset app.
Google street view which gives access to aerial photos as well as street view
UK Tides - (free) FR Tides - (free, covers French ports including Caribbean and FP) PocketGRIB - (Lite is free only 2 days but the Pro version gives 8 days) Marine Weather Pro by Bluefin (couple of quid) Boat Beacon (AIS tool but costs about £3 ? )