I think it's actually like $5,000,000.
It was $1 million up to 2010. The Tax Relief, Unemployment Insurance Authorization, and Job Creation Act of 2010 was passed by Congress and signed by the President that December. The lifetime exclusion is $5,120,000 for 2012. $5 million is the 2011 figure.
That and the Bush era tax legislation will come to an end December 31, 2012 unless extended. If it is not extended the figure is $1 million in 2013.