by sebastiano » Mon Oct 31, 2011 4:16 am
See here: http://www.uspto.gov/products/library/ptdl/locations/ptdlib_1page3.jsp
There are two:
Learning Resource Center, Bayamón Campus, University of Puerto Rico
General Library, Mayagüez Campus, University of Puerto Rico
Be aware that these are depository libraries. In general, you'll need to file with the USPTO in Washington, DC (Alexandria, VA, actually).