We currently have an ECommerce integration module that synchronizes data between TRS and a website. The ECIM currently supports an integration method that requires the website developer to write a service to respond to requests from the ECIM. I would like to add support for Zen Cart (an open source shopping cart system).
I know that it's possible to integrate with Zen Cart by directly connecting to its MySQL database and directly reading/writing the tables. However, many web hosting companies block direct access to MySQL on their servers. I'm not sure if Zen Cart provides a more friendly API or not. This would be something for you to research.
The ECIM uses a C# interface called IWebsiteProvider. You would need to create a new class that implements the IWebsiteProvider interface. When you accept this project, I will upload the interface definition.