A site i really enjoy using is
http://www.20000-names.com/ (Though it isn't agreeable with the latest version of FireFox. I have to use the Tab button like crazy if i want to do a search on anything.)
In general with online name sites you want to be careful. It's not uncommon for them to list a name with a meaning that isn't factual.
Still... they can be lots of fun and give plenty of ideas. With 2N I can get a feeling for a language and then go to the library if i want to look more in depth into that culture's names.