From Steam Heavy Industries:
Encyclopedia provides a complete copy of the Wikipedia encyclopedia on your iPhone/iPod. This app is the fastest and simplest way to browse Wikipedia on your device and crucially doesn't require any internet connectivity. It works in a plane, on top of a mountain and when abroad. (Or, if you're an iPod Touch user, whenever you don't have a wifi connection.)When you first launch Encyclopedia, you will be required to download a copy of the database which will occupy about 600MB of space on your device.For frequently asked questions, please head to http://collison.ie/wikipedia-iphone/faqFEATURES-No internet access required-Complete text of the French Wikipedia*-Instantaneous livesearch of article titles-Fully functional links between articles-Navigation trail, so that you can easily engage in the usual whimsical Wikipedia browsing.*Some parts of the articles that aren't very useful on a mobile device (such as references) have been excluded. All of the actual article text is preserved. In addition, only proper articles are downloaded - image descriptions, user profiles, etc..., are not included.
Improved navigation Bookmarking Multiple databases (foreign language dictionaries, copies of Wikipedia in foreign languages, Wikitravel) available in addition to FrenchADDITIONAL AVAILABLE DATABASES Wikipedia Encyclopedias: English Wikipedia Spanish Wikipedia German Wikipedia French Wikipedia Dutch Wikipedia Japanese Wikipedia Italian Wikipedia Irish Wikipedia Arabic Wikipedia Hungarian Wikipedia Indonesian Wikipedia Farsi Wikipedia Chinese Wikipedia Turkish Wikipedia Russian Wikipedia Finnish Wikipedia Vietnamese Wikipedia Hindi Wikipedia Greek Wikipedia Catalan Wikipedia Hebrew Wikipedia Wiktionary Dictionaries: Spanish Wiktionary German Wikitionary Italian Wikitionary Wikitravel Travel Guides: Wikitravel