Mexico

Country Code +52

NOTE: On 4 November 2006, the format for dialing mobile phones in Mexico was changed.
For mobile phones, the digit "1" must follow the country code and precede the area code.
Example: +52-1-Area Code-Phone Number

If the place you're looking for isn't listed above, try this comprehensive list.

 Also, you might try the TelMex Area Code Directory.

You can also look up changing codes on this TelMex search page.