twython is an actively managed python wrapper for the Twitter and Twitter Streaming APIs. All functions are mapped to the coinciding endpoint in the Twitter docs, providing developers with a lot of flexibility.
Twitter has a popular iPhone app, but now some of its functionality is also built into Apple's latest mobile operating system, iOS 5. Tweeting a photo from the default camera app is now a tap away, as is tweeting a link from Mobile Safari. Tweeting is also built into the SDK, making it available via other applications without needing separate Twitter authentication.