Nokia announced this morning that Ovi Maps for its smartphones, including turn-by-turn navigation, will be free from now on — an inevitable result, I suppose, of two things: the rapid transformation of maps and navigation on mobile devices from paid or subscription to free, catalyzed by Google’s move late last year, and Nokia’s acquisition of Navteq in 2007.

Notably, maps are available globally (Google’s is, for the moment, U.S.-only) — that’s leveraging your Navteq purchase. Nokia also allows caching — handy when you’re roaming (expensive, but precisely when you need mobile maps) or can’t get a signal.

More at All Points Blog, AnyGeo, Engadget, Mapperz, Slashgeo and The Tech Chronicles; Engadget has a hands-on.