From the Wall Street Journal:

Former Secretary of State Colin Powell said he wasn't interested in serving in a new administration under President-elect Barack Obama, saying he wanted a new generation of leaders to step up.

“I am not interested in a position in government, nor have I been approached,” said Gen. Powell, who was traveling in Hong Kong. The former Army general and secretary of state under President George W. Bush said the election marked a generational shift in the U.S, and that he would always be available to offer advice. “I'm not expecting to go to government,” he said.

When asked specifically about whether he might serve as Secretary of State or Secretary of Defense, Gen. Powell shrugged it off, saying: “Why? I've done it.”