I just finished creating the first implementation of a PHP library for the Constant Contact API. It does almost everything the REST APIs allow. There are some features that I will add in the future, but everything from adding/editing/removing Contacts/Lists/Campaigns/Subscriptions is in there. In addition I created a SourceForge project for any developers interested in getting involved. Here are the details:
I noticed that external resources had Java and Python and seeing as how PHP is so pervasive I thought it deserved the same thing. While I love the Constant Contact API and think it is the best thing in email marketing out there, please remember that I am not a developer for Constant Contact or officially sponsored by them. However, maybe they will give me a nod and link to the project on the "External Resources" page. ;)
Please let me know of any comments, questions, or suggestions you may have about the project.
Thanks for the PHP library! We appreciate your efforts and thank you for releasing the project to the public. Hopefully, the library will help other developers with their integration work, and they will help make the library even better in the open source environment.
I'll make sure to put the library in our External Resources page.