Baby Names.com: The site displays names in lists that are easy to scan, plus you can sort by orgin of name. Handy if you’re writing fantasy, and you want to stay in the same name family for continuity. The mouseover popups are a bit annoying though.
Baby Name Box: This has a fairly extensive list of name orgins you can sort by. The site has an annoying popup, and the search by letter feature is not working.
Social Security’s Popular Baby Names: Search by decade for the most popular name. This was great for picking an older character’s name when I wanted him to sound a little out of date.
Common Nicknames: This is a genealogy guide to figuring out what a person’s real name was if everyone only knew them by a nickname.
World Family Names: See where a last name pops up across the globe. Very handy if you want geographical references.