Current federal law (Title 3, chapter 1, section 6 of the United States Code) requires the states to report the November popular vote numbers (the “canvas”) in what is called a “Certificate of Ascertainment.” You can see the Certificates of Ascertainment for all 50 states and the District of Columbia containing the official count of the popular vote at the NARA web site at http://www.archives.gov/federal-register/electoral-college/2004/certificates_of_ascertainment.html
http://www.archives.gov/federal-register/electoral-college/2008/certificates-of-ascertainment.html
The ascertainment has to be delivered on or before the day the electoral vote is made. Maybe “Compact” states will have to send 2 slates of electors if they can do that.