XOWA is a desktop application that can read and edit English Wikipedia offline. It displays articles in an HTML browser, and can download images on demand. It can also be used for Wiktionary, Wikisource, Wikiquote, and the non-English counterparts.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.