SearchinQ

http://www.castles.org/
Reference for castles, palaces and monasteries including: castle tours, medieval architecture, hotels, travel, plans, weddings, castles for sale, souvenirs, books, directory, site of the week, and history of castles.

http://www.castlesontheweb.com/
A collection of sites that offer information and pictures to castles from around the world.

http://www.great-castles.com/
Offers links to castle home pages, photographs, myths and legends, and virtual castle tours.