Language exchange. It helps if you already know some of the basics of a language, but if you can find a language partner or two that are fairly advanced in your first language then they will often be willing to start from the ground up with you on their first language. My favorite language exchange site so far has been http://www.myhappyplanet.com since they have a good format for being able to state your languages and skill levels, as well as your education goals and what you can offer a language partner in return for their help. While I had an intermediate-level understanding of Spanish at the time I started (and REALLY increased my understanding through talking to people from all different parts of the world), I also had a couple of language partners whose first language I knew nothing about...French and Chinese...and was able to pick up quite a bit from them as well. It's completely free, it's basically like social networking for language geeks :P.