Songs and movies are invaluable, especially if you can find movies with subtitles in your language. Rosetta Stone is good as well, though, as the first response pointed out, it is quite expensive. Personally, I learned to understand Spanish (although not as well as I'd like) by watching soccer on Spanish language television. I know the terminology of the game in English, and hearing people describing familiar situations in Spanish helped me to learn the language, even a few colloquialisms. Immersion is the key, I think, to learning any language quickly. Spend as much time as possible each day hearing, reading, or speaking the language and you may surprise yourself at how quickly you learn.