– National Geographic has put together a very cool interactive map of surnames across the US. I’d love to see one of these for other countries, honestly.
– Baby Name Wizard’s Name Mapper – see where and when a name was most popular, by year from 1960 to 2009. (US only, as far as I know.)
– My favorite Wikipedia category: Surnames. (I particularly love the lists of common surnames by country. So useful!)
– Behind The Name is great for finding first names by country, especially when you’re looking for things like ‘Cornish’ and ‘Breton’.