On iTunes at: itunes.apple.com
With Duolingo, you can learn Spanish, French, German, Portuguese, and Italian, all for free! There are no ads and no hidden charges. You can even invite friends to use the app and compete with them in language challenges! The app gives you the opportunity to translate real-world phrases into the language you are learning. According to an independent study (static.duolingo.com) funded by the app makers, "34 hours on Duolingo is equivalent to one semester (11 weeks) of a college language course."