GeneaBloggers and Genea-Musings, Ancestry.com has added more Pennsylvania death certificates. Its database now contains the images from 1906-1963. Previously, it only included records up to 1944.
The great thing about having this collection on Ancestry is that a surname search may help you discover children in your family tree that you didn't know about. In my own experience, I found several cousins who were born and died between censuses, and they may have remained "unknown" until I searched these death certificates.
Keep in mind, though, that the records added in the last batch had many transcription errors, so use wildcards to make sure you don't miss anyone. Since even cities were transcribed incorrectly--like "Pittsburgh, Oa" and "Moline, Hleriois"--surnames will definitely have errors as well. Be sure to try multiple wild card searches for the same surname to cover all possible spellings.
Please post a comment if you find any interesting details about your Pennsylvania ancestors after searching this database.