Hi, I studied abroad in Bilbao at the Universidad de Deusto, my classes were with spaniards but I believe they also have classes for learning spanish, semester and summer programs, not sure how it works but if you want to study spanish in bilbao its a good place to start. Even if you arent looking for a university program, and are needing more of a language school kind of set up the director at deusto is wonderful and could probably point you in the direction of a school or two. I actually specifically remember there being a private languge school that taught both english and spanish as well as french, it was in the deusto district just down the street from the deusto metro stop. I can't remember the name right now though. Id really recommend Bilbao as a place to study spanish though, it is wonderful.... not too touristy, not too many extranjeros and a really intersting and different culture. In the summer you have the added perk of being just a metro ride away from some beautiful beaches.

Suerte!
Kelly