MapQuest, the No. 2 Internet-mapping service after Google's, is taking the first steps toward a Wikipedia-like model -- in which users would generate the maps themselves and combine the results for everyone to use.

The company, a subsidiary of AOL, plans to announce Friday morning that it is launching a site in the U.K. based on a project called OpenStreetMap, which is dedicated to user-created mapping. The OpenStreetMap project has caught on most quickly in Europe, which is why MapQuest is starting there, but AOL also will...