Under the Telecommunications Act of 1996, since 1 July 1997 Guam and the CNMI have been part of the North American Numbering Plan and treated by law as a domestic part of the United States, as well they should be.
Rate integration applies here, similar to Hawaii and Alaska.
Some American telecommunications companies and calling plans still treat Guam and the CNMI as "international" destinations requiring the "011" prefix from the rest of the U.S., but they are violating the law.
Most likely it is inadvertent failure to update their software, just like the mailing companies that don't include the "GU" and "MP" atate/ territory codes on their mailing address software pull-down menus.
http://www.usps.com/ncsc/lookups/abb...ns.html#states
Whenever I have found such a company, I sent them a polite letter notifying them of their omission, and asking that they comply with the law so I do not need to contact the Federal Communications Commission about the matter.
[Paragraph separation.]
[This message has been edited by SPN Lifer (edited 02-12-2003).]