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 Federalist" articles appeared in three New York newspapers: "The Independent Journal", the "New-York Packet", and the "Daily Advertiser", beginning on October 27, 1787. Although written and published with haste, "The Federalist" articles were widely read and greatly influenced the shape of American political institutions. Hamilton, Madison and Jay published the essays at a rapid pace. At times, three to four new essays by Publius appeared in the papers in a single week. Garry Wills observes that this fast pace of production "overwhelmed" any possible response: "Who, given ample time could have answered such a battery of arguments? And no time was given." Hamilton also encouraged the reprinting of the essays in newspapers outside New York state, and indeed they were published in several other states where the ratification debate was taking place. However, they were only irregularly published outside New York, and in other parts of the country they were often overshadowed by local writers.