How would I locate the rules of law that are to be followed in a wrongful termination/discrimination case that have been filed in Philadelphia County Court
There are no special rules. The general rules are in the PA Code and can be viewed free of charge at:
http://www.pacode.com/secure/data/231/partItoc.html
You will have to read the local Philadelphia County rules. There are several law libraries in Philadelphia. They might also be online.