This is nice. I’m pretty sure it’s not the entire Patrologia Graeca, but it’s certainly easier to read than scanned pages of the print PG for what is there. The caveat here is that, so far as I can tell, these *.pdfs don’t contain volume/column information, so you’d still have to refer to the print/scan edition for citation details.
But hey, why quibble?
Leitourgeia kai Qurbana: Contra den Zeitgeist 
Logos Bible Software recently released for pre-order an electronic edition of Migne’s Patrologia Graeca.
This version of the PG will be fully searchable, linked to English translations in Schaff’s Early Church Fathers, and contain a number of other features that simply don’t work with a simple pdf.
Thought you might be interested!