Calling Singapore from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 65 - Country Code for Singapore
• Phone Number - 8 digits; first digit is 3 or 6 for VoIP lines and 6 for landlines
• US to Singapore international dialing format: 011 65 ???? ????

How to dial to Singapore cellular:

• dialing format for calls to a cell phone: 011 65 8??? ???? (or 9??? ????)

Phone Books:

• Yellow Pages Singapore