Simple Signup for WordPress gives you the ability to collect your visitor’s email address with this simple and fully customizable (and translatable) sign-up form. To get up and running with the plugin, you merely have to enter your API information from Campaign Monitor, and get to customizing the pre-generated sign-up form that you are provided with.
Some of the key features of this great integration are:
Simple Signup is priced at $18. To take a test drive or read more about it, you can check out their site.