OpenStreetMap is an example of a phenomenon known as Volunteered geographic information (VGI) – the harnessing of tools to create, assemble, and disseminate geographic data provided voluntarily by individuals. OSM is one of the most prominent examples of this movement and rather than the map itself, the data generated by the OpenStreetMap project is considered its primary output.
OpenStreetMap lives by the claim that anyone can be an editor and to make that possible, the tutorials at Learning OSM just keep getting better! There is no better place to start than this site which takes user from novice to advanced and also offers pointers to many of the initiatives such as HOT OSM that are putting OSM to real world use. Learn the necessary skills and find out where you can put them to use.