[askwhy]

CoPilot is pretty good -- not as slick as Garmin in my opinion (who will have their own android phones soon), but a reasonable alternative -- of course, it's also not free.

If you root and flash a custom rom with Donut (1.6) or higher you can use the updated Google Maps (with Turn-by-Turn) -- and that is a good free option, but still dependent on a good signal for internet.

Are there other good options? I would also like to know.