Use the search box on top right to search the wiki for the right page to answer your question. The Map Features page is useful for finding out how to tag a wide range of features. The Mapping projects page has information about many projects within OpenStreetMap on particular subjects or for particular countries/territories.
- help.openstreetmap.org provides forum-style questions & answers for common issues.
- switch2osm explains how to use OpenStreetMap instead of other services.
- Mailing lists cover all topics and are the official routes of communication for issues like licensing
- IRC: IRC is a free chat service that provides instant help.
- Forum: Forum (for which You will need an OpenStreetMap account to be able to post replies and create new topics).
- FAQ covers many common questions with official answers.
Communities on other sites
- Facebook: Facebook group
- LinkedIn: Linkedin group
- identi.ca: 'OpenStreetMap' group
- Wikipedia: Wikipedia OpenStreetMappers
Use the Beginners' guide to learn how to start contributing map data to the project. If you are interested in help on software development then head over to the Develop page. Use Wiki Help to find information about how to contribute to this wiki; the main discussion venue for the wiki itself is is at Talk:Wiki.