The world is your classroom, and there's no better way to experience the language and culture of Germany than by diving right in! Below are a number of links to study abroad programs for high school and college students.
Goethe Institut - learn German all over the world! http://www.goethe.de/
Study Abroad Links For High School Students http://www.studyabroadlinks.com/search/Germany/Programs_for_High_School_Students/index.html
Academic Study Abroad Opportunities in Germany http://www.studyabroad.com/simplehtml/germany.html
The Friendship Connection I would highly recommended this one, and I can guarantee that you won't find a better price for such an opportunity anywhere. The program is really well run. http://www.friendshipconnection.org/