Inheritance taxes aren't imposed on the whole estate--instead, they're owed by the people who inherit property. Still, it's the executor's job to see that these taxes are paid before the inheritors actually take possession of their inheritance.
Inheritance Tax Overview
Here are the basics of the inheritance tax, including how it differs from the estate tax.
State Inheritance Taxes
There's no federal inheritance tax, and currently just a few states impose a state tax. But if you inherit property--no matter where you live--you can find yourself owing inheritance tax.