The Suburban Realtor Alliance, serving Bucks, Chester, Delaware and Montgomery Counties has put together an excellent resource for information about the municipalities within those counties. It provides an interactive map, and detailed information about each municipality. They include information about any restrictions on For Sale and Open House signage, which can save you from inadvertantly violating a local ordinance.
SRA also provides information valuable to Consumers looking to purchase property in the area. Their Consumer Page contains valuable information.
As I gather more Chester County Links, I will post them here, for your easy reference. If you find anything else useful, please post it in a comment.