Android: The official Wikipedia app for Android lets you save articles for offline viewing, search articles pertaining to your location, share articles, and more without the need for a mobile browser.
Wikipedia has had an iPhone app for awhile, and now it's finally available for Android users to try. Not only can you save articles for offline reading, but you can view your article history, read an article in any language with a few taps, and see what local landmarks have Wikipedia pages. The app is fast and responsive, too, and a solid replacement for Wikipedia's mobile page. Not to mention it's another way to access Wikipedia during its SOPA blackout.
Wikipedia is a free download for Android devices.
Wikipedia for Android | Android Market