There was indeed information that could have warned the US of the attack, but red tape tied things up until it was too late. The US knew that Japanese diplomats were beginning to destroy certain documents and files as early as December 1st. However, a second arm of the Japanese diplomatic corps was still talking peace in Washington at the time of the attack so American optimism probably helped delay the realization of the “message.”
There wasn’t, however, an actual coded message sent and intercepted that would have warned us if we had paid attention. See today’s New York Times article ( http://www.nytimes.com/2008/12/07/us/07pearl.html?em ) for details of the recently released report.
The US knew that war with Japan was coming and had known for some time, but the possible timing of the potential attack was only laid out in November 1941, where Roosevelt et al realized that Japan couldn’t wait much longer to attack.
But we hoped and assumed it would be the Philippines that would be the target. There was in fact an attempt to trigger the attack there involving a civilian yacht that was sent to “spy” on Japan. This was in part to solve the “Philippines problem” (ie, how to give them their independence since we had gained them from the Spanish-American War) and in part to prevent any damage to the Pacific fleet.
I don’t recall off-hand all my sources for this but I did a report on this for American History and used several compilations of government reports and communiques for the basis of this information.