Lilja's Library- Regarded as THE site for general Stephen King news and information. One of only two fan sites listed on stephenking.com
Thedarktower.com - The largest and most active SK forum site on the net covering all aspects of Stephen King, including rare books.
Charnel House- This site has tons of Stephen King info especially book facts, reviews and current news. After a long hiatus is now being updated regularly; Check it out!
The Signed Page - A website devoted to bringing signed and personalized books to those fans who are unable to meet with their favorite touring writer. Unlike a typical bookstore this site does NOT charge a premium for signed books. Currently has signed Gunslinger comics as well as other non Stephen King books.
Club-StephenKing - A french site devoted to all things King. They also have a very active twitter feed.
Stephenking.com - The official Stephen King website, complete with an active forum.