I haven't personally used LingQ, but it seems to be the best way to pick up new languages. It provides a feed of news in other languages with a neat vocab tracker! I haven't learned a language with it yet, but I'm very interested. There's also an excellent interview with LingQ's creator.
I've used it personally and it's fantastic. If you're like me, the most productive language study is just reading and looking up the individual words you don't know. LingQ facilitates that beautifully.