This law was vetoed by the president of Mexico in 2006 and sent back to congress for review:
- http://www.eluniversal.com.mx/nacion/137975.html
Then it was finally approved on April of this year:
- http://www.tribunalatina.com/es/notices/mexico_despenaliza_l...
Edit: corrected description of links. Thanks PieSquared for noting the veto.