Book reviews and analyses

Barnes and Noble - often has reviews from Booklist, Library Journal, and more.
CliffsNotes - study guides, book summaries, and more
Literary Criticism - from the Internet Public Library
Literature Resources database - biographies, bibliographies, essays and critical analyses
Pink Monkey - literature summaries, plus study notes on other subjects
SparkNotes - study guides, message boards, complete texts, and more
What Do I Read Next? - book recommendations based on genre, title, author, series, and more