This has been asked so many times I'm rather reluctant to answer again . . .
If you click 'search' at the top, or go through the language sections of the site, you'll find a lot of various threads that discuss this, all discussing the pros and cons to various methods and what ways there are to learn a language. The link below is what one kind poster put onto the language section of the site a while back, it's a comprehensive list of all the sites other posters gave within a particular thread that help people to learn Japanese:
Japanese Language Resources