>>1, there is an expanded answer for you after the rant. Feel free to jump ahead. :-)

>>13
Well, I'm speaking from personal experience too. (English is not my first language; and I'm taking Japanese in college now.)

Classes are good. Learning grammar is good. Having a good teacher is invaluable. And if you want to spend all your spare time learning on your own; guess what - that's perfectly fine too. One does not exclude the other.

But going at it on your own? Lots of people do that, and quit pretty soon after. That doesn't mean it's impossible of course. But it takes dedication. For a given random poster on a discussion board, that is not something you can just assume.

Therefore: >>1, if it's available to you, take a class and find out if this is something you really want to do. A good class, one where you learn hiragana and a few kanji right away. Make sure you have a good teacher, a native speaker if possible. Spend as much time as you can, and as much as you feel like, studying on the side. Hang out with the other guys in class. Try all the technical tools available to you (like the Rikaichan Firefox extension, a flashcard programs for your PDA/phone, maybe an electronic dictionary if you can get one).

Then decide how to continue. Maybe complete immersion is the way to go for you; maybe not. But you'll have no idea what it's like until you start.