On the new MacVoices (http://www.macvoices.com),Glenn Fleishman updates his December 2009 look at iPhone navigation apps, outlining what is new and what has changed since he initially spent lots of time driving around Seattle testing them.

He compares and contrasts app-based navigation with dedicated hardware devices, identifies three key issues that need to be accounted for if you are going to let your iPhone guide you to your destination, and talks about some hardware accessories you might want to explore. The latest enhancements in display options, why sunglasses and your iPhone don’t mix and features that contribute to convenience and safety are all covered.

Fleishman also looks at how the download vs. live-over-the-air apps compare with DVD-based dashboard systems, why iPod control considerations are important, and how well all classes of apps handle points-of-interest.