Great stuff latinaviation.
Here are a few others:
Asociacion Sindical de Pilotos Aviadores de Mexico
Caribbean ALPA
Jamaican Airline Pilots Association (JALPA)
Sindicato de Pilotos de Lan Chile
Pagina no oficial de los pilotos de Iberia (not Latin American, but see the "Destinos" then "Miami Hub" section for some great information about Iberia's destinations in Central America from a pilot's perspective)
Corporacion Centroamericana de Servicios de Navegacion Aerea (COCESNA) The agency responsible for ATC and navigation services for Guatemala, Belize, Honduras, El Salvador, Nicaragua, Costa Rica and a large part of the Western Caribbean waters. Their site also has Notams for this area.