You have two main options when it comes to GPS apps for the iPhone: apps with offline maps and apps with online maps. Examples of apps with offline maps are the Navigon, the iGo My Way, TomTom, or the recently added Magellan RoadMate.
These apps are excellent for frequent users as they don't require a live data connection to work. All the maps are included with the app and downloaded to the phone. However, they tend to require gigabytes of storage space and take a long time to install. If you plan on going on a long road trip, they are good fits.
If you are a casual user, however, it's better to use an online GPS application. These applications are just a few megabytes in size and therefore take a few seconds to download to the phone via a 3G connection. This means you can immediately get one the moment you suddenly need turn-by-turn directions.
The first online GPS app for the iPhone is the AT&T Navigator, which works pretty well. Unfortunately, it's only available to AT&T customers and is rather expensive ($10 per month) for what it offers. The good news is, you now have other and more flexible choices. … Read more