Classicgaming is ok,
but you should definitly look
here first Rhylan.
They´ve got all the stuff you´ll need, and not just for NES, but all the other systems too, even arcade. Two good windows based NES emus are NNNesterJ and RockNESX. You can get them at the link I posted. If you´ve got any troubles setting them up just let me know.