Here are examples of web-sites which focus on musical styles and performers from different parts of the world:

The World of Music
http://library.thinkquest.org/11315/

Africa
http://ancient-future.com/africa.html

India
http://ancient-future.com/india.html

Bali
http://ancient-future.com/bali.html

http://www.knockonwood.co.uk/

http://www.worldmusic.net/

http://www.rootsaroundtheworld.info