Calling Cuba from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 53 - Country Code for Cuba
• Phone Number (may not begin with 0):
  • fixed - 6 to 8 digits including area code
  • cell phones - 8 digits
• sample call from US to a landline in Havana: 011 53 7 ??? ????

How to dial to Cuba cellular:

• dialing format for calls to a cell phone: 011 53 5 ??? ????

Area Codes (by county):

Phone Books:

• Paginas Amarillas - official Yellow Pages, in Spanish