In addition to Clint's summary, here are the rest of the changes for 2013:
+ Two (2) bottles per entry are required in the First Round.
+ The tiebreaker rules for the Ninkasi Award have been changed/expanded due to the 15 entries per person rule.
+ There are 11 Judge Centers in the U.S. this year. These have been registered with the BJCP, but here is the list of cities with First Round competitions: Seattle, San Francisco, San Diego, Denver, Tulsa (OK), Kansas City (MO), Saint Paul, Milwaukee, Atlanta, Zanesville (OH), and New York City.