According to the Federal Institute of Telecommunications (IFT for its acronyms in Spanish) since August 3rd, the way we dial in Mexico has been changed. Now it will be much easier.
Prefixes that are deleted:
In other words, if you are trying to call from Canada or USA to Mexico you should dial 011 + 52 + 10 digits.
For calls inside Mexico (Mexican number to Mexican number) you must dial 10 digits.
Emergency numbers remain without changes.