Build Recurring Income

I am going to be receiving ongoing income from my grandfathers estate. I have been told that it is taxable because it is classified as income not an inheritance since it is income earned by the estate since his death. I an trying to get an idea of what tax rate I should expect to pay. I do not know yet exactly how much I will be receiving.

Serving as executor - both parents passed in 2005. How is the Estate and Income Tax handled for both New Jersey and Federal returns on Annuities and Life/Term Insurance. Not sure what is taxable as Income and what is taxable to Estate. Also, not sure who pays the taxes, beneficiary or estate on the income tax - assuming there is a income tax liability.