Always when trying to integrate a Mailchimp Newsletter Subscription into WordPress manually, there are a lot of problems occuring. In this very short tutorial I will explain how to create a working, customizable form.
1. The Mailchimp backend. Go to:
Lists -> Forms [from the desired list] -> For your Website -> Signup Form embed code Choose "Classic form" and chose your options and get the embed code.
2. Avoid jQuery conflicts and problems
3. Make your own, custom CSS
Remove the stylesheet link at the beginning of the mailchimp form or modify the style. You could use this
reference. You also may want to delete the "err_style" in the jQuery script. Change the labels in the form to the desired language. Thats it .. don't know why they do not offer a customizable no conflict form...