Bill,
Sorry, but I don't know of any good web resource for phrases. I don't like the way "Faci'm" sounds -- too much like a fairly haughty order. Porti'm or Dona'm are fine for "bring me", voldria prendre is very sophisticated, but sounds great. Sisplau (please) and gracies or merci (thank you) are important, as is "Em pot cobrar?" (check please). I agree with David that learning some Spanish (español, not castellano) will probably offer a better ROI.
Matt, update your map, Catalonia is a "Castillian country" (sic) and has been since 1710 or so. While a Catalonian will appreciate a phrase or two in Catalan, they will be equally comfortable with a tourist taking the effort to speak in their other language, Spanish.
In any event, in Barcelona, it is becoming increasingly rare to find Catalonian waitstaff, so Spanish might just be an easier way to make oneself understood.
By the by, Bill, "cabrón" is a frequently used word in Mexico, but here it is not appropiate except among friends or people who are looking for a fight.
Enjoy your trip.