From the blog post announcing the service:
Many of you have shown deep interest in working with us to build maps, and have been demanding to be made part of the map-making process. Now, in response to that demand, here’s YOUR chance to help fill those remaining gaps in our maps! :)
We’ve just launched Nokia Map Creator, a fun tool on maps.nokia.com that literally lets YOU map out your local neighbourhood! You can also use Map Creator to make small edits and additions to existing maps. The tool is super simple to use. The best thing about it is that your work will be visible to all maps.nokia.com users — immediately! Your Map Creator content will also be shared via regular map-data updates for Nokia Maps on mobile and web, after NAVTEQ validation checks.
The initial focus is on 'previously unmapped' countries, including Uzbekistan, Kyrgyzstan, Tanzania, Angola, Burundi, Sri Lanka, El Salvador, Dominican Republic, Jamaica, Antigua and Barbuda, and Grenada.
In those parts of the world, your work will complement and help speed up the continuous work of our dedicated Nokia Maps team.
Map Creator already lets you draw streets and footpaths. You can also name new streets and add key information such as driving directions, vehicle type characteristics or paving type. But that’s just the start! You will soon also be able to add even more types of map content such as parks, forests, lakes and rivers. In short, all the types of content you are familiar with seeing in Nokia Maps!
Link: Nokia Maps Creator