Kana

• kana de manga (book)
• realkana

Grammar

• minna no nihongo (book)
• genki (book)
• guide to japanese
• the japanese page
• jgram
• tae kim's guide to japanese grammar

Kanji

• remembering the kanji (book) by james w. heisig + reviewing the kanji
• anki
• read the kanji
• japanese kanji dictionary

Practice

• lang-8
• evernote

Vocabulary

• iKnow!
• create your own flashcards with anki
• memrise

Dictionaries

• denshi jisho
• alc

Blogs

• Learn Japanese - The Why, The Truth and The How
• How Should You Learn Kanji?
• How to Learn Kanji - Using Heisig's Method to OWN the Japanese Characters!
• Studying Japanese and Korean
• Another way to learn two languages at the same time (THIS entries are useful too if you're learning both)
• Japanese and Korean, A Second-Pass Comparison: Verbs