There's a String Theory Tutorial at UC Santa Barbara. You can also find a tutorial, links, and oddities at The Official String Theory Web Site. And there are many links at Superstrings! String Theory Links.
At the Amazon bookstore you can read a generous excerpt from our textbook. Here are reviews of the book:
Here's Brian Greene's home page at Columbia University, and two short interviews:
Here's David Morrison's home page at Duke University.
Here's a biographical sketch of Ed Witten. And, straight from the horse's mouth, here are his notes on Duality, Spacetime and Quantum Mechanics. You have been warned!
Here's a Scientific American article about M-theory and branes. On the same subject, John Schwarz at Caltech has written Superstring Revolution, part deux.
Finally, here is a list of some New York Times articles on physics. To read the Times online you need to register, but there is no charge.
Home page for "The Elegant Universe" course