The people at Calvin College's Philosophy Department have created an on-line library of papers by well-known Christian philosophers in the Protestant, especially Reformed, tradition. Here is the site's self-description:
Calvin's Philosophy Department houses one of the finest undergraduate philosophy programs in the nation. Calvin's Philosophy Department was the undergraduate and/or teaching home of four American Philosophical Association Presidents—Alvin Plantinga, Nicholas Wolterstorff, William Frankena and O. K. Bouwsma.
At present the Library holds 177 articles, with some of the listed authors having no articles represented, while Alvin Plantinga has twenty. The site's address is: http://www.calvin.edu/academic/philosophy/virtual_library/