As part of our special Abandoned City collaboration with CityPaper, Technically Philly, and programmer Tis Wisniewski, City Paper obtained a list, current as of March 2011, of all land believed to be vacant in the city. Here's the raw data for vacant properties.
The spreadsheet below is a Philadelphia Water Department of buildings for which water service has been shut off.
If you haven't seen it already, check out the interactive map created by Tim Wisniewski using City Paper's data, and showing properties that have been conveyed by the city's Redevelopment Authority that still (for various reasons) remain vacant.
A few notes: