Bartleby, classic works and reference books online
A Book a Minute, highly condensed classics, science fiction, and bedtime stories. Irreverent, but it's a hoot. The site even has a movies link.
SparkNotes, better at online study aids than its more famous cousin, CliffsNotes. These sites are for students, of course. But teachers will enjoy the user's comments sprinkled throughout the SparkNotes site.