Regarding navigation in N9, check this page.

I will point out that the N900 also stores the maps on the device (doesn't have voice navigation). However, the designers decided that your N900 would never be without a data connection. Therefore, searching and routing functions were off-loaded to a server somewhere (Finland?). While that works fine when you have a data connection, if you don't have one, you can't search or route on the N900 using Nokia maps. Surely nobody would ever get lost where they don't have data service right?

While the advertising looks promising, there is still information missing. Show me a "free" OFFLINE mapping/navigation solution, and I'll call it fully functional. Voice navigation isn't a necessity for me. Frankly, the driving view looks pretty old school, not up to par with current offerings. Which leads me to question how well it works.

*For the record, google maps/navigation is not a fully functional solution (IMHO) either as it doesn't store the maps, and needs a data connection for searching and routing.