Google has launched a new tool that allows users to contribute and edit Maps data for regions around the world called “Google Map Maker.” In a similiar move, Microsoft has also launched a new tool for Virtual Earth imagery called “GoVE” that lets user upload, edit data to Virtual Earth.
Google Map Maker allows you and your peers to add, edit and moderate most features you see on maps including roads, lakes, parks, points of interest, businesses, cities and localities. You will be able to trace many of these features using satellite images; as you trace, maps are immediately updated
you can build maps in the countries of Cyprus, Iceland, Pakistan, Vietnam and the Caribbean nations of: Antigua & Barbuda, Bahamas, Barbados, Bermuda, British Virgin Islands, Cayman Islands, Grenada, Jamaica, Netherlands Antilles, St. Kitts & Nevis, St. Lucia, St. Vincent & the Grenadines, Trinidad & Tobago. The existing mapping data for these countries could benefit tremendously from local knowledge and expertise that you and other map makers posses, and we're excited to see how you put that to use.
This wiki offers more information about locating features and tutorials for all the tools that can be used to improve the maps. “This product is a labor of love by many engineers based in Bangalore who have a desire to see the world mapped,” explains Google.
Another collaborative mapping service is OpenStreetMap, that licenses all the data as Creative Commons Share-Alike. The project's motivation is to create a "a free dataset which will enable programmers, social activists, cartographers and the like to fulfill their plans without being limited either by Google's API or by their Terms of Service. [Google System]