Another iPhone App that I am finding indispensable in bike explorations is Maplets. Maplets is an archive of simple specialized maps that typically cover a very small region. Think tourist brochures, university campus maps, chamber of commerce town maps, official National Park or National Monument maps, public transportation maps, or trail maps that have been printed by the local riding club.
We've just had this 'app' pointed out to us by our friend Joe Cruz. After a continent spent asking men with donkeys at track junctions the way, any way of accessing decent local maps is always a good thing!