From North America to Palma de Mallorca: dial 011 (int’l access code) + 34 (Spain’s country code) + the local number.
From Mallorca calling North America, dial 00+1+area code+local number. Many US long-distance phone companies have access numbers that you can dial in order to use your phone card, usually through the Spanish telephone company public phones, LADATEL. Calls may be less expensive than direct-dialed calls from your hotel room. (Check with your hotel for surcharges BEFORE calling.)