Beef Checkoff Modernization Act of 2008 - Amends the Beef Research and Information Act to direct the Secretary of Agriculture to establish and maintain (as a subcommittee of the Cattlemen's Beef Promotion and Research Board) an importers qualified beef council to promote nondomestic beef or to pursue any other authorized purpose of a qualified beef council.
Replaces the definition of "qualified state beef council" with a definition of "qualified beef council" that includes an importers qualified beef council.
Requires a beef promotion and research order to provide that: (1) at least 30% of U.S. producer assessments be made available to promote and market products derived from cattle born and raised in the United States; and (2) the importers qualified beef council reserve a percentage of its funds to promote products derived from cattle not born and raised in the United States, or for any other purpose allowed under this Act for any other qualified beef council.
Requires the Secretary, beginning in 2010 and at least every seven years thereafter, upon receipt of a petition of a group comprising 10% or more of cattle producers, to conduct a referendum to: (1) determine whether cattle producers favor the termination or suspension of the order; and (2) vote on any other amendments to the order.