After finding new mentions of navigation and maps technology in the legal section of iOS 5, MacRumors did some sleuthing and believe Apple is working on their own replacement for Google maps on the iPhone. [MacRumors]
It might just be a better UI and data set on top of existing Google Map data.
Google Map's are the best when it comes to actual map design in terms of contrast, information density, etc. Every time I use another map service it is really annoying what color choices, line thicknesses, and other such decisions are so poor.