Turns out Gonzalez can authorize a wiretap for up to a year under FISA as Georgia10 points out:

First, let me point out that under Section 1802, the government can wiretap a foreign power for up to one year without a warrant. Not 72 hours. An entire year. This provision is applicable when the Attorney General can “certify” that the information is used only for foreign intelligence purpose. It requires certainty, but that provision is available to the administration.

Check out her entry at Daily Kos, it is filled with some fun facts including how much Bush has actually used FISA. I remember one of the Senators making a statement during Monday’s hearings that they extended the time a tap could be conducted without a warrant after 9/11. I wasn’t sure how long they extended or what the grounds were but apparently this is what they were talking about.