The USPS (United States Postal Service) 3w.usps.com offers 2 different usually offered ways to send merchandise to Mexico:

1) Priority Mail Service – cheap – slow – you have to pick your delivery
2) Express Mail Service – more expensive – faster – deliver to your house

As USPS is not a transnational company, it "links" with other's countries Postal Services in order to deliver packages. In Mexico, that service is called "Servicio Postal Mexicano" (SEPOMEX) 3w.sepomex.gob.mx

Be aware that if your seller declared in the invoice the item's nature and value, it will pass more quickly thought the custom office (Aduanas Mexicanas). The taxes for almost anything goes from 15% to 451% (if Chinese origin), 67% if it is a textile and so on. You can see at Aduanas Website at 3w.aduanas.sat.gob.mx

SEPOMEX has a little branch called "MEXPOST" that has a true delivery system to your house or business; the usual "priority mail" does NOT reaches your home (they do not even call you). If you are lucky and pushy, your delivery will end in your city SEPOMEX building and YOU have to go to pick it. The express service from USPS gets the "MEXPOST" service; which is more expensive but faster and nicer.

Be aware that your USPS Track number only works con USPS page until the shipment leaves the U.S.; as it gets into Mexico, it will not reflect any change. Your track number is the same for SEPOMEX and you can track your package (maybe with 2 or 3 days delay) in the SEPOMEX page.

Another different service (maybe useful for you if you need it fast and can afford it) is called Merkalink (a service in alliance with Estafeta Mexicana), you can see at 3w.merkalink.com

Sorry for the links; eBay does not allow links outside eBay pages. The links I posted begins with "3w" that means "www" (3 times "w") in order to bypass the filter.

I hope this can be useful for you (and do not forget to vote “YES”, please).