The non-profit Wikimedia Foundation is the parent organization of Wikipedia, Wiktionary, Wikiquote, Wikibooks, Wikisource, Wikidata, and other projects. Its goals are to maintain and develop open content, wiki-based projects and to provide the full contents of those projects to the public free of charge.

Official site: http://wikimediafoundation.org/

Contact information including local chapters is available there.