Usability 
Yahoo's Driving Directions Web app is GPS aware, but works on most phones using a text address input box where you can enter street address, city/state or zip.
The address parser seems quite forgiving in what it accepts, ignoring case and punctuation and handling abbreviations and truncated city names well. Yahoo remembers the last four locations entered and allows you to reuse them. You can also choose a location from your saved Yahoo Favorite Locations. A small route overview map sublements the turn by turn directions.