Matthew Poer

I wrote this plug-in mostly as an attempt to learn more about creating WordPress Plug-ins, but I think it is potentially useful for certain folks and so I am releasing it as an open-source, unsupported piece of software. I hope you enjoy it.
The goal of the plug-in is to help a WordPress Site Administrator integrate a MailChimp mailing list into the WordPress site. Once the plug-in is installed, you must provide a MailChimp.com APIKey, then select a list to enroll your visitors to.
The default widget is practical, but not very pretty. Basically, it includes a typical widget layout containing three input fields, one hidden field to track the page URL, and a submit button. The HTML for the widget can be customized to fit your site and WordPress theme. If you choose to do this, please don’t try to change the input fields’ NAME or ID attributes. It won’t work if you change these.

MailChimp Newsletter Widget

The goal of the plug-in is to help a WordPress Site Administrator integrate a MailChimp mailing list into the WordPress site.

Mahfuzar Rahman

The MailChimp plugin allows you to quickly and easily add a signup form for your MailChimp list as a widget on your WordPress 2.8 or higher site.
Not sure what <a href="http://www.mailchimp.com/features/full_list/" rel="nofollow ugc">MailChimp</a> is or if it will be helpful? Signup up for a <a href="http://www.mailchimp.com/signup/" rel="nofollow ugc">FREE Trial Account</a> and see for yourself!
After Installation, the setup page will guide you through entering API information, selecting your List and then add the Widget to your site. The time from starting installation to have the form on your site should be less than 5 minutes – absolutely everything can be done via the WordPress Setting GUI – no file editing at all!
<h3>Developer Mode</h3>
You can enable “Devleoper Mode” by adding the following line to your <code>wp-config.php</code> file just above the “That’s all, stope editing!” line.
<pre><code>define('MAILCHIMP_DEV_MODE', true);
</code></pre>
This will enable the MailChimp List Subscribe plugin to operate without the need to connect an external MailChimp Account, and will provide a 
subscription form widget that will not actually submit anywhere.
This will allow you to style and configure the widget in non-production environments that are not publicly accessible.
For more Developer Mode customization options see the following article:
http://connect.mailchimp.com/how-to/how-to-article-configuring-developer-mode-for-the-list-subscribe-wordpress-plugin

Easy Mailchimp Optin Form

The MailChimp plugin allows you to quickly and easily add a signup form for your MailChimp list as a widget on your WordPress 2.8 or higher site.

MailChimp Newsletter Widget vs Easy Mailchimp Optin Form