Ancestry.com has the following databases:
New York Marriage Notices, 1800-55
New York, Marriage Newspaper Extracts, 1801-1880 (Barber Collection)
Brooklyn, New York Catholic Church Marriage Records, 1839-1900
New York City Marriages, 1600s-1800s
FamilySearch has THOUSANDS of books:
http://books.familysearch.org (search for New York marriages)
This free website has HUNDREDS of New York newspapers:
http://fultonhistory.com/Fulton.htmlA few other free New York websites with marriage info: (I've only listed the ones within the timeframe you want)
Brockport, Monroe County
http://www3.libraryweb.org/uploadedFiles/MCLS/Local_History_... [yes, the misspelled file is the right one]
Montgomery County, N.Y., marriage records
http://www.archive.org/details/montgomerycounty00lethMarriages recorded at Reformed Dutch church, Manhasset, Long Island
http://www.archive.org/details/marriagesrecorde00manhMarriages at Jamaica, L.I.
http://www.archive.org/details/marriagesatjamai00jama