Ron:
Please be so kind and read first the Mexican Banking Regulation before you will move forward with your offer.
http://www.iln.com/articles/pub_193.pdf
http://www.iflr.com/?Page=17&ISS=16428&SID=515304
http://www.mexicanlaws.com/?gclid=CIX5p87I144CFSUMIgodpHSO-g
http://www.banxico.org.mx/ (if you understand spanish)
You may receive feedback from people who want to "exchange" some Pesos against USD but not through Banking Instituts (i hope you understand what i mean) and this can bring you in serious legal problems.
Note: I am based in Mexico and that's why i know what i am talking about.
DDrep
Thomas