Repealing a provision limiting the unified credit used to determine the Maryland estate tax to the amount corresponding to a $1 million exclusion amount under the federal estate tax; repealing a requirement that the tax be determined without regard to the deduction for State death taxes under the federal estate tax; repealing a requirement that a person responsible for paying the inheritance tax file an estate tax return and pay the estate tax under specified circumstances; and applying the Act to decedents dying after December 31, 2005.