Ovi Maps for mobile shows you were you are with better than ever street maps, satellite, terrain maps, and 2D and 3D views. And it shows you what you need nearby with millions of local services and points of interest worldwide.
Ovi Maps for mobile is free to download or may be preinstalled on your Nokia.
I upgraded to version 3 after I got the phone (it came with version 2).
It works well with the GPS receiver (as you'd expect) and doesn't require an Internet connection to work as all the data is loaded onto the phone. The maps scroll beautifully and are detailed down to the smallest roads. However they are road maps, there are no footpaths or other rights of way shown.
The data includes points of interest (POI) information which is split into categories. From your current location you can find the nearest petrol station, cinema, etc. Some categories are well covered, it showed all of the petrol stations in my area for example, but other categories, notably shopping, were very patchy.
As a free, simple mapping application it works well but it didn't do everything I wanted. It'll be useful for navigating a strange town or city especially when I am on foot. As it doesn't use an Internet connection and additional maps are free to download it would useful for navigating when abroad, where an Internet connection is very expensive.