I first took a look at the Skobbler crowd sourced GPS app for iPhone back in June of 2010. I found it uneven in quality, but it was free, and if you weren't going to spring for one of the big boys like Garmin, Navigon or TomTom it was worth a try.
Skobbler has now been updated, and it costs US$0.99. The app has been renamed GPS Navigation 2. Your dollar gets you US and Canada maps in a universal application that adds local search, a "take me home" option, integration with your contacts and iPod playback while navigating. The maps are from OpenStreetMap, kind of a Wikipedia for mapping. Using the map requires a data connection, but you also have the ability to download maps at prices ranging from $5.99 for North America, Europe, and Australia to $3.99 for places like Italy, Ireland, the UK, France and Germany.
How does it work? It's still a mixed bag. The maps are clear enough, but operation is quirky. You get a 3D map, but if you scroll to the right it suddenly turns 2D. Scrolling left doesn't get you the 3D map back; you have to hit a "back" button. As I drove, I didn't always see my car centered on the map, and I often drifted off screen. Navigating back home was a complete failure, as I was told to turn onto a street that did not connect to where my house is.
The app advertises local search. I tried "grocery store." Nope. Pizza? Zip. Pizza Hut? Uh-uh.
I tried some non-residential addresses and they worked fine, and the voice for turn-by-turn directions was audible and pleasant. The app provides a female voice with a soothing British accent.
There are some other inexpensive nav apps. Motion X GPS Drive comes to mind at $0.99, but features like voice directions cost extra and are subscription based. Waze is a free, crowd sourced nav app, and it gets consistently good reviews.
If you aren't about to buy a more expensive navigation app, and you feel lucky, this app might be worth a look. The GUI has been considerably improved from the older version, and the added features are nice. On the other hand, if it can't get you home, it's really not a good investment, even at $0.99. Screen shots are below.