Business Contact Manager 2007 SP1

After importing contacts from ACT, my US customers have been imported with
"United States, USA" in the country field. Because of this, the Zip Code
shows in the business card before the city/town. If I change the country to
"United States of America", everything corrects itself. I have over 3000 US
contacts. How can I look up by the "country" field and change them all at
the same time.