Just a head's up. Mexico's Federal Telecommunications Commission "Cofetel" has published the official Mexican AM station list in .PDF form again. The list is dated May 31, 2012. This is starting to become a regular thing of late, as the last update was just two months ago. Kudos to them!
Don't be mislead by the 2008 date in the site link. After downloading the PDF, you can find the actual list date at the bottom of the document.
This list can be made into a nice spreadsheet form by converting the saved PDF document to an XCEL (.XLS) file. If you don't have the software to do that, a great, free online conversion site can be found at Zamzar on the web.