Hola mvtm y bienvenido!
As far as I know, there are no current bonus offers just for opening an AAdvantage account.
You can however benefit from earning bonus miles each time you reserve and purchase tickets on aa.com (up to 250 miles for coach and 500 miles for business flights). Although this bonus was withdrawn for US members, it still applies to us here in américa latina. Here's the extract from the Argentina aa.com site:
"Esta bonificación aplica únicamente para socios AAdvantage residentes en Argentina, Bolivia, Brasil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, México, Nicaragua, Panamá, Perú, República Dominicana, Uruguay y Venezuela que reserven y compren su boleto vía AA.com o AA.com/español."
Suerte!