Barcelona has constructed a "new" cruise ship terminal at the Moll Adossa, across the harbor from the World Trade Center. (it's actually a converted warehouse). It's a long walk from the Colon Monument (at the foot of Las Ramblas) over a high bridge to get to the cruise ship pier. Instead, you can catch the blue bus from the Colon Monument (there's a little kiosk on the harbor side of the street) to the cruise ship terminal for $1.50. Go to www.portic.net
for maps of the harbor area.