Primary Research
newspapers & magazines • unpublished manuscripts • government documents • Digital Philadelphia
Unpublished Manuscripts
Philadelphia Area Consortium of Special Collections Libraries
http://www.pacscl.org/
PACSCL is a web portal for 33 specialized libraries and archives in the Philadelphia area; 20 of the institutions have at least some of their collections included in PACSCL's joint catalog. This can be a neat site to browse, particularly if you are in need of finding a topic. Definitely a resource to know if you are doing research on Philadelphia.
National Union Catalog of Manuscript Collections
http://www.loc.gov/coll/nucmc/
NUCMC, pronounced Nuck-muck by its devotees, covers manuscript collections in the United States. After you get to the NUCMC page, choose OCLC Worldcat in the middle column. NUCMC and Worldcat used to be different tools; they are converging, but NUCMC is still useful to focus returns on archival collections.
Worldcat
Worldcat, the electronic database that is a good tool for finding secondary sources, also allows you to search for archival sources. Check the box for "archival materials" when you run your search.
Many, many archives have at least a minimal web presence, which means that Google's regular search engine has a pretty good shot at finding collections that various archives hold.
In the First Person
http://www.inthefirstperson.com/firp/index.shtml
This is one of the electronic resources available both through the library's databases page and through the open web. It is a portal to thousands of oral interviews done around the globe, including some relevant to Philadelphia.