Go to http://www.firstdistrictplaza.com/1089345.html.
The sales (mortgage foreclosure, tax lien and tax collection) are held monthly at First District Plaza, 3801 Market Street. At the sale, you will find documentation identifying the advertising dates for the various sales. Newspapers including advertise the sales. By law, notice of pending Sherriff's Sale must be made in advance, so complete listings of the properties scheduled for sale will appear in publications such as the Daily News, Philadelphia Tribune and The Legal Intelligencer at specific times in the weeks preceding the sales. Some words of advice: go to a few sales to see the process in action and try to pick the brains of some the sheriff sale “professionals” who are there on a monthly basis. I'm sure they won't tell you all of the tricks, but you will probably up some helpful information.