I was reviewing the news about free navigation for Ovi Maps and was wondering... Nokia told that by March every phone will be shipped with free navigation.

Unless they say that N900 is not a phone, it should be included as well. Since for basic routing Ovi Maps for Maemo seems that it is missing just to add the voice guidance, maybe they can release an intermediate update (i.e. PR1.1.1) until March to accomplish that... Just speculation, but how knows!!