You can also check out
CDnow.com, or another cd megasite, check out foreign or domestic artists you've never heard of, or who use instruments you've never seen. Most of the time you can listen to snippets and see if it interests you.
I don't use many samples, but the vocal samples I have used generally come from Jazz, Zouk, or R&B.
Foxy Brown's last album had a beat on it which used a sample from some middle-eastern music, the vocal sample matched the music and made up the whole chorus section, I could tell the language was Arabic. I think Timbaland used some middle eastern stuff too, but no vocal samples.