If it's street mapping you're after, I just picked up Copilot
from ALK for my Windows phone, it's also there for iPhone, iPad, and Android.
Uses the phone's built-in GPS, keeps maps in memory (not online) so it's self-contained. Makes the phone comparable to a basic Garmin or Tom-Tom. You can pick a destination, tap "Go," and it calcs the route. Voice directions, with text-to-speech for spoken street names. You can set speeds and preferences (expressway better than 2-lane, avoid tolls, etc.,) add stops and waypoints to the route, search POIs both in the memory and online. iPhone prices look like 20 bucks for the North America map set with the Live online features, only 5 bucks for the US without the online feature set, and I think the iPhone version has a 30-day trial.
Like the very basic GPS devices, you can't save a route to re-use later, no can you move data back and forth between this and your computer.