Matt Leighton is a missionary, local church elder, and professor at El Colegio Bíblica de la Gracia in Spain. Over the last few years he's produced, in Spanish, a number of theological resources from a Reformed perspective. The resources (audio and papers) are all available for *free* at the website of Grace Bible Church (see below).
Please pass on the link to anyone you think may be interested in these excellent resources.
Links:
About Matt Leighton
Reformed theological resources in Spanish by Matt Leighton
Ryan Wentzel