Calling East Timor from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 670 - Country Code for East Timor
• Phone Number - 7 digits for landlines and 8 digits for cell phones
• sample call from US to a landline in East Timor: 011 670 ??? ????

How to dial to East Timor cellular:

• dialing format for calls to a cell phone: 011 670 7??? ????

Updates:

• East Timor telephone numbering changes - July 2012