[Rogozhin]

I don't know how effective self-teaching is given the difficulty of learning any new language.

I strongly recommend you memorise all the hiragana and katakana first before delving further. This isn't too difficult to do on your own (just keep at it and practise writing/reading/listening/speaking them)

I think you should definately consider joining a class though, because it just gets more difficult from here.

I can't offer you any online teaching sites I'm afraid.