Etymoline: Online Etymology Dictionary. This is an excellent resource for finding that perfect word that you need to help you describe your 1640's scene. Don't know if it's period correct? Look it up!
Medieval Names: Get your names right in your medieval tales!
Baby Name Finder: One resource for selecting the perfect character names.
Baby Name Inventor: Don't like what you see in the Baby Name Finder? Check out this site and invent one! I particularly like their Arthurian Legends category. Like being in a candy shop!
Fiction Factor: A very useful resource for writers to explore. Lots and lots of links!