BluRay has 3 regions:
A - North America, Central America, South America, Japan, Taiwan, North Korea, South Korea, Hong Kong, and Southeast Asia.
B - Europe, Greenland, French territories, Middle East, Africa, Australia, and New Zealand, plus all of Oceania.
C - India, Bangladesh, Nepal, Mainland China, Pakistan, Russia, Central, and South Asia.
However, it is up to the studios what individual titles actually use region coding. So a number of releases have come out that simply use none at all.
Here's some links to help you find what ones are region free. Granted, they aren't all inclusive lists, but they are regularly updated.
http://www.blu-raystats.com/stats.php
http://bluray.liesinc.net/