Calling Qatar from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 974 - Country Code for Qatar
• Phone Number - 8 digits for all regions including the capital Doha
• US to Qatar (landlines) international dialing format: 011 974 44 ??? ???

How to dial to Qatar cellular:

• dialing format for calls to a cell phone: 011 974 XX ??? ???
• XX can be: 33, 55, 66, 77

Phone Books:

• Ooredoo - Qatar White Pages
• YellowPages.qa - Yellow Pages

Updates:

• Qatar telephone numbering changes - July 2010