For the Android world saddened by the exclusivity of Google Maps Navigation to Android 2.0 (free turn by turn directions), be excluded no more: Google Maps Navigation is now open for all devices running Android 1.6.
Google has also upgraded the application to now include layers of information such as transit information, Wikipedia articles, or geographical points of interest. A great app is now a better app.
Of course, do not expect stellar performance on an earlier Android phone, but the app is free, and according to the community, amazing. Be sure to grab it if you use Android. We iPhone users need no such useful and free bit of software. We have folding paper maps.
The application is in the Navigation section of the Android Market right now, it remains US only.