Today's (London) Times reports that the S. Korean government is afraid that Americans will "take out their anger and shock over the shootings at Virginia Tech on Koreans living in America". I certainly hope not. The Washington Post says that "every Korean person is so very sorry". They shouldn't be.
I think Americans will recognize that despite the fact that Cho Seung Hui was originally from Korea , for all intents and purposes he was American. He'd been living in the US since he was 8 years old. His formative years were spent in the US, not Korea. And, from the little we know about him so far even his disturbed mind-set he hated "rich kids" is an attitude that could be held by Americans of any descent.
Cho was a disturbed man. Maybe he would never have become a killer if he'd remained in Korea, but the fact that he emigrated from there is no indication that there's any flaw in the character of Koreans or any reason for any Korean to feel shame for Cho's actions.