The year 2010 has been a good one for the beneficiaries of large estates, but their lawyers need to be prepared for significant changes on the horizon.

Congress repealed the federal estate and generation-skipping transfer taxes for 2010. In a $10 million estate, for example, the repeal represents an estate tax savings of $2,925,000 as compared to 2009. Unless Congress takes action, however, the federal transfer tax system will return with a vengeance at the stroke of midnight on Dec. 31. The same $10 million estate will incur $4,795,000 in estate taxes in 2011, a 64 percent increase from just one year ago.