Integrating 123FormBuilder web forms with iContact is as easy as 1-2-3. Visit your 123FormBuilder Settings -> Applications sections, choose iContact in the dropdown list and press Add. Provide your iContact username and password and click on Save. Choose the iContact list where you want to add contacts and press Customize.
In the iContact web form customization lightbox that appears, you need to establish field associations between 123FormBuilder and the iContact application. Simply put, you'll match your web form fields with iContact fields. Select, in the dropdown lists on the right side, the form fields corresponding to each iContact list entry. Press Save when you're done.
Learn more about 123FormBuilder - iContact integration.