Which area(s) West of Philadelphia were you looking at? There are 3 counties with many townships/boroughs and towns and they all do things very differently.
Please email me where you were interested in and I'd be happy to do the research for you!
Your realtor has access to real estate tax information for virtually any home you would be interested in buying. I'm familiar with Newtown Square and surrounding areas, including Broomall, Havertown, Media and West Chester. If I can be of further service, please feel free to contact me anytime.
For example, Philadelphia would be: http://brtweb.phila.gov/
When you are ready to search the properties, you can use our site at http://www.thesomersteam.com .
Your next step would be to find a top notch buyers agent for the area that you are most interested in.