We are looking to write a prestashop module that will allow us to integrate our e-mail marketing system (12all) with prestashop. 12all has very clear api examples of how to hook into prestashop. They've already have free plug-ins for wordpress and others. I have complete detailed specifications for this project. Prestashop currently has an option to subscribe to newsletter and optin. we would pass on these selections and emails to 12all via the api and subscribe them to a specific list.