Amends the Internal Revenue Code to allow a business tax credit for the production and use of biodiesel fuel. Specifies the required mixture rate for biodiesel fuel eligible for the credit. Requires, for purposes of the credit: (1) certification from the producer identifying the product; (2) sale of the fuel for use in a trade or business; and (3) sale of the fuel for use in a vehicle that is not registered for highway use. Imposes a tax for biodiesel mixture which is not used as fuel, but for which a credit was taken.