Some random notes on learning German...
German Sentence Structure
Lingster Academy - Clear, beautifully spoken German lessons
Your German Teacher - Excellent grammar and usage explanations
Lingoni German - Beginner to Intermediate lessons, with both formal and colloquial usage
My German Short Stories - Clearly spoken short stories with vocabulary explanations
Deutsch Lernen Mit Der DW - Many lessons, including the Nico Weg movies for beginner to intermediate
Easy German - Conversational German with street interviews and many examples
Galileo - Documentaries in German (Intermediate)
Duden.de - The source of all truth
Your Daily German - English explanations of German words, useful for getting the flavor of words
German.net - Massive resource of clearly explained grammar, usage, sentence structure
Verbformen.com - Conjugate/decline German words (verbs, nouns, adjectives, etc.)
German Language Course - Wikibooks German Course - beginner to advanced beginner, phrases, usage, etc.
Goethe.de - Official language materials with links to certification, courses, etc.
Easy German Learning - Multimedia files geared to learning by listening
DuoLingo - Learn many languages via exercises, daily repetition