North Korea, as a whole, is clearly anti-American. South Korea is less clear. Older South Koreans are pro-America as expected, but younger generation seems to be leaning toward anti-American sentiments. Focus of anti-American sentiments in South Korea is not based on differences in idealism, but apparent imbalances in the relationship between American and South Korea. Whether justified or not, young South Koreans are proud of their country and America threatens that pride.
There are Korean kids who maintain detailed list of all the incidents caused by American soldiers such as rapes, beatings, and how the guilty escaped justice thanks to the mighty America. Passed through several people, these stories gets bloated and turn real ugly. Result is kids thinking South Korea is under the occupation of America. Bush's actions and words nudge that kind of thoughts further along their paths.
I am not saying we'll see freedom fighters in the streets of Seoul anytime soon. But I am concerned about the trend because there seems to be no significant counterforces. Generation-gaps dilute influences by the older generations. Internet actually makes the problem worse because most South Korean kids shun non-Korean sites and communicate almost exclusively among themselves, thus amplifying negative feelings.