Google is making its mobile Navigation app available in more countries, throughout Europe: Austria, Belgium, Canada, Denmark, France, Germany, Italy, the Netherlands, Portugal, Spain, and Switzerland. It's voice guided and offers voice search. In a related development, Google expanded the number of European languages for Google Voice Search.
Google's free Navigation (which works well) has not yet come to the iPhone, whether for technical or competitive reasons. However a new free app from Berlin-Germany based Skobbler offers free turn by turn navigation on the iPhone. I haven't used it so can't comment on its quality. It uses OpenStreetMap for base data.
Finally, Google Maps are now a part of GM's OnStar functionality. Users can email directions from PC-based Google Maps to select GM cars. Ford has also integrated Google Maps into its Sync system and will allow users to send directions to Sync from the PC or smartphones. Sync was co-developed with Microsoft so I would expect comparable functionality for Bing.