Sant Cugat, about five miles from the city, was designed by Colt in 1919, but it was destroyed (during the civil war I believe) and rebuilt by Javier Arana. Unfortunately Arana's course has been fairly heavily changed since.
Arana also built El Prat, but it was sadly lost because of the expansion of the Barcelona airport and replaced by a 45-hole Greg Norman complex.
PGA Golf de Catalunya is an upmarket resort about an hour north of Barcelona, near the city of Girona, frequently voted the best course in Spain (best PR campaign imo). Nice property but I find the course underwhelming.