Universitat Politècnica de Catalunya (UPC)

Barcelona is a bilingual town, and to be honest I would have to say that Catalan is the first language. Of course everyone understands and speaks Castellano (Spanish) perfectly, but quite a few people will (for political or other reasons) prefer Catalan. It is perfectly possible to live here without speaking or understanding a word of Catalan, but at least understanding it will certainly make you feel less of an alien. Studying at the UPC, you will certainly come across classes in Catalan, especially at the school I went to (ETSEIB - Industrial Engineers), which has about 90% of its classes in Catalan.

There's an office which job is to help foreign students to find an appartment. It is expensive but efficient.