Some Basic Resources on the History of the Church in the Philadelphia Area

Here is an article by church member Daniel Rolph, for the Historical Society of Pennsylvania.

Mormonism in Early Philadelphia

Here is a brief, generic review on the Church website.

The Church in Pennsylvania

Here is an even briefer Wikipedia article. It needs some work.

The Church of Jesus Christ of Latter-day Saints in Pennsylvania

And here is a much longer, but unsigned article.

Philadelphia Mormon History