It's Nokia maps which is on a few phones now.
I have it on my N95. It doesn't provide voice navigation out of the box, but you can purchase a licence for varying prices depending on where you want to navigate and how long (There was a 12 month trial for Ireland and the UK included with my N95, so check if you get that). Even without the voice navigation it will still tell you your position anywhere in the world, provided you have the maps installed. The one thing to watch out for when roaming is to preload the maps as if you are using it abroad and the map is not available, it tries to download it (you can imagine the cost)
As far as the mapping software goes, it's good, and nearly on a par with stand alone gps. It's easy enough to use, and the voice directions are good. If you take a wrong turn, it recalculates quickly. It saved me one day when I took a wrong lane at the Mad Cow roundabout on the way to an exam one day.