Apple's iPhone comes with a free navigation application based on Google Maps. But unless you've dash-mounted your phone or have a co-pilot reading the directions, it's not exactly driver friendly. For real hands-free driver help, you need voice turn-by-turn directions.
TomTom and other standalone GPS makers sell iPhone app versions of their popular GPS systems. but they cost about $70. I figured I'd get my feet wet with a cheaper approach, and installed VoxTrek, a $3 app that offers free worldwide maps and voice-synthesized directions. It also provides information on speed cameras, and gives you a variety of direction set options—for driving the fastest route or shortest distance, bicycling or walking.
There are two small issues with VoxTrek. It has an amusing-bordering-on-annoying voice synthesizer. Aside from the robotic monotone, it occasionally stumbles over common abbreviations. Valmont Pkwy became "Valmont P-k-why". A street named Woodlawn Drive, because of the "Dr." abbreviation on the map, was spoken as "Woodlawn Doctor."
Then there are the directions themselves. VoxTrek uses routing information from Cloudmade Maps' OpenStreetMap, which uses maps made by a community of volunteers in their free time. If volunteers haven't mapped where you're going, things could get a little interesting.
Things started off fine with VoxTrek, until I was exiting the Interstate. The software got confused and started telling me to make a u-turn on the exit ramp, even though I was on the proper route. This may have been because of GPS interference within the car, or a glitch with local maps. After pulling over to try and figure out what went amiss, the phone blurted at me, "You go wrong way."