The Department of State has eliminated the need for an approved petition from United States Citizenship & Immigration (USCIS) prior to applying for a TN visa at a US consulate.  Under the new rules, any qualified Mexican professional can apply for the TN visa directly at a US embassy or consulate office.  This ruling is in effect as of Feb 10, 2014.

The elimination of the first step will dramatically cut down the processing time on both ends of the process.  Win win!

More details here:

DOS issues final rule for Mexican citizens applying for TN visa classification

Mexican TN Visa – New Procedures Streamline Processing