BigMailChimp is a WordPress plugin by arianKhosravi and NorikDavtian that enables the user to host their MailChimp capture forms on their own website without the need to write a single line of code. Moreover, you can display your capture forms as widgets or as standalone forms on individual posts. Simply create/modify your forms on MailChimp and the effects will take changes on your site instantly.
Features:
Generates capture forms based on MailChimp lists
Easily host your capture forms on your site
Display multiple forms
Display forms in pages or posts
Display forms as widgets site wide
Easy to use interface
Short code generator
Plugin homepage: http://bigemployee.com/projects/big-mailchimp-wordpress-plugin/
Download: http://wordpress.org/extend/plugins/bigmailchimp/