Here are some of my favorite links for German stuff:
Leo has a real nice German-English English-German dictionary. It also has a nice search plug-in for FireFox.
Deutsche Welle lets you read and listen to news in German. It also has some nice lessons for learning German.
German Language at About.com has a lot of good information for learning German.
This site is designed to teach you German using the Harry Potter books. Naturally you are going to have to buy the books in German to do this. I bought my books from Amazon.de, it was cheaper than buying the German books from Amazon.com