There is already internet in North Korea. Although it's only available in universities. The rest of the country got a intranet (although access to this is probably rare, as most North Korean's probably don't have a personal computer).
But, if the entire population of North Korea were to get access to the internet uncensored things would have changed rapidly.
The reason the dictators in Egypt and Libya were overthrown is because of social networks enabled the people to communicate and rise against their dictator.