Awsome thread,
I too have some sites and android apps i can recommend
Apps:
Obenkyo
I wondered why nobody has mentioned it yet. This app is awesome. It has a learning site and a test mode. Obenkyo covers Hiragana, Katakana, Numbers, Kanji (sortet by school level and jlpt including a dictionary and stroke order) vocabulary, patikel, and grammar. The app is regulary updated. The only thing that doesn't work for me is the writing test. My fingers won't fit their neat demands. But the rest is great.
Kanji recognizer
If you want to find a kanji in a book or magazine or something you can use this app. It also has a test mode. The only problem is they go by stroke order, but if you're used to write kanjis, you should be able to look the right kanji up
http://www.japanesepod101.com/index.php
I believe i haven't seen this site yet. It has tones of material you can learn with. Most of it needs a registration, and for somethings you have to pay. But with the registration you'll get the pdf files and such.
And I have three links for germans:
http://www.din1031.de/verben/?jis=0&load2=ulist
Hilft beim konjugieren von Verben und man kann kanji texte in kana umwandeln lassen (helps with the conjunction of verbs and you can convert kanji texts into kana)
http://lingweb.eva.mpg.de/kanji/
german kanji dictionary
http://www-user.tu-chemnitz.de/~heha/j/buchtext/Index.htm
Ein komplett digitales Lehrbuch mit Audio (whole digital book with grammar, vocabulary and audio)