Starting in 2011 widows and widowers can add to their own estate tax exemption the unused exemption of the spouse who died most recently. This provision, plus an increase in the exemption amount to $5 million per person, enables married couples together to transfer as much as $10 million tax-free to their children or other heirs, either by making lifetime gifts or through estate plans. This 2-year provision expires January 1, 2013
see: http://www.TaxEsq.com