Reporters Without Borders Internet censorship ratings.      No censorship      Some censorship      Under surveillance      Internet black holes (most heavily censored nations)
Persavive censorship: Burma, Cuba, Egypt, Iran, North Korea, People’s Republic of China, Syria, Tunisia, Turkmenistan, Uzbekistan, Vietnam
Substantial: Bahrain, South Korea, Saudi Arabia, United Arab Emirates, Yemen

Source: Internet censorship article on Wikipedia