does an american need a passport to go to mexico
No but, PROOF of citizenship and photo ID is needed. Birth Certificate. A Drivers Licence is not that proof
As of today, no. See http://travel.state.gov/travel/tips/brochures/brochures_1229.html#m
However, note that the rules here are rapidly changing, both for people who cross into Mexico on foot or by cruise, and by air. You should look for the link on this page for the Meixcan Embassy for the latest info.
The real problem is not you getting into Mexico but you getting back into the U.S.
From the same page: "On effective dates below, all travelers to or from the Americas, the Caribbean and Bermuda will be required to have a passport or other document that establishes the bearer’s identity and nationality to enter or re-enter the United States. On December 31, 2006, the requirement will be applied to all air and sea travel to and from Bermuda, the Caribbean, Central and South America, Mexico, and Canada. On December 31, 2007, the requirement extended to all air, sea, and land border crossings. For more information or to confirm effective dates, visit the State Department’s consular web site www.travel.state.gov or the U.S. Department of Homeland Security’s web site at www.dhs.gov."
So, as soon as you can, get the passport...
You'll need it when flying back... no visa though.
Canovas 8, Col. Centro, Xalapa, Veracruz, 91000, Mexico
Benito Quijano No. 10, Col. El Tejar, Jalapa
Dr. Rafael Lucio No. 186 Colonia Centro, Jalapa
Av Ruiz Cortines #912, Jalapa