At least he didn't say it depends what "is" is: From Slate:
Monday, Bush called Harken's initial accounting of the Aloha sale "an honest difference of opinion as to how to account for a complicated transaction. … Sometimes the rules aren't as specific as one would expect." He explained to reporters that "in the corporate world, sometimes things aren't exactly black and white when it comes to accounting procedures. ... Sometimes there's differences—an ability to interpret one way or the other."

Tuesday, Bush demanded "higher ethical standards—standards enforced by strict laws … Our schools of business must be principled teachers of right and wrong, and not surrender to moral confusion and relativism. Our leaders of business must set high and clear expectations of conduct." Bush pledged to "end the days" of "shading the truth," and he declared that honest businessmen "do not cut ethical corners."

The headline on the Slate front page is "Business ethics are black and white, except when they're mine." William Saletan ends by zinging: "Bush was elected on a promise to end the contradiction between presidential rhetoric and presidential rationalization. So far, all he's done is change the subject from sex to money."
http://slate.msn.com//?id=2067870