http://www.sparknotes.com
2. Ace Your College Classes
http://www.aceyourcollegeclasses.com
3. CliffsNotes
http://www.cliffsnotes.com
4. NovelGuide
http://www.novelguide.com
5. Schoolbytes.com
http://www.schoolbytes.com
6. PinkMonkey.com
http://www.pinkmonkey.com