PhillyHistory.org, an online repository of more than 43,000 historic photos covering the history of the city of Philadelphia has now gone mobile.  PhillyHistory Mobile is the portable companion site which offers a geographic-based search interface where users can query by address, intersection, keyword, or historic date to find nearby historic or cultural sites.  A list of results is returned to the user, and clicking on any one of the results brings up the photo along with a map of the photo’s location.  The search capabilities are built using ESRI’s ArcGIS Server and ArcIMS software.