President Clinton was somewhat more upbeat about progress that former President Jimmy Carter announced last week during his visit to North Korea. Speaking on NBC's "Today" show, Clinton pointed to a proposed summit between the two Koreas as a sign of a potential diplomatic warming. He was more cautious about the centerpiece of Carter's trip: a reported agreement by Pyongyang to freeze its nuclear program. "We have surely something to gain by talking with the North Koreans, by avoiding further steps toward a crisis," said Clinton. "But we have to know there's been a change."