Original meaning
Originalists of all stripes cite "The Federalist Papers". It is fairly tenuous to suggest that this represents a good source for the original "intent": after all, Alexander Hamilton, who wrote the majority of those essays, was absent for the greater part of the Philadelphia Convention, and John Jay did not attend it at all. However, James Madison, the principal framer of the Constitution also wrote a substantial amount of "The Federalist Papers". Also, to suggest Hamilton and Jay's absence from the convention implies their ignorance as to the Constitution's original meaning is demeaning to those two men and inaccurate. The collected anti-Federalist papers, of course, will be no use at all to a person searching for the original "intent" of the framers. However, as evidence of how a reasonable person at the time would have understood the words of the Constitution, "The Federalist Papers" and the anti-Federalist essays are evidence of direct relevance.
The Federalist Papers
The amount of deference that should be given to "The Federalist Papers" in constitutional interpretation has always been somewhat controversial. As early as 1819, Chief Justice John Marshall noted in the famous case "McCulloch v. Maryland", that "the opinions expressed by the authors of that work have been justly supposed to be entitled to great respect in expounding the Constitution. No tribute can be paid to them which exceeds their merit; but in applying their opinions to the cases which may arise in the progress of our government, a right to judge of their correctness must be retained." In a letter to Thomas Ritchie in 1821, he stated that "the legitimate meaning of the Instrument must be derived from the text itself; or if a key is to be sought elsewhere, it must be not in the opinions or intentions of the Body which planned & proposed the Constitution, but in the sense attached to it by the people in their respective State Conventions where it recd. all the authority which it possesses."