Nah, listening to stuff while you sleep doesn't really help. It just makes you... unable to have a good night's sleep. Really. When you wake up how much of what you heard in the night will you remember? Barely. =/
Me too, i wanna learn japanese, because when i grow up, i´ll go to Japan
The best effective way to learn japanese is to take a course/class. One of my friend's friend is doing just that and is progressing fast. But if there isn't a class nearby or don't want to spend money here are my best options: watch anime and somewhat understand the dialogue and/or get a japanese course book at ur nearest bookstore
Very true. Take a class, preferably one that is taught by a Japanese teacher (who is also well-versed in English), or someone who has lived in Japan for long enough to know his/her way around the language & modern slang.