Language learning and translation

Just saw a TED talk from Carnegie Mellon, about work being done on large scale human computing....  Okay, that part was interesting too....

But what caught me is a free way to learn a new language.  They are in beta testing at http://duolingo.com/.  The idea is to learn a new language by translating words.  The original learn to do by doing...  But structured so that what you are doing is something that also helps translate web pages.