New York, Probate Records, 1629-1971, is a wonderful collection now available on FamilySearch. Genealogists researching New York ancestors will indeed be thrilled to find this material online.
Forty-five out of New York’s sixty-two counties are represented. (Counties south of Delaware, Albany, and Rensselaer are excluded, as is Schoharie.) The collection is browsable, but has not been indexed and is not searchable. The content and year range of the probate records vary by county; for some counties there may be a general index to probate, for others there may be an index to wills only. Most records end in the 1920s with some indexes continuing to 1971.
This morning, I found the Letters Testementary for my 3x great grandfather, Ebenezer Bemis.