WPSubscribers is a premium WordPress plugin that will help you to attract loads of new subscribers to your mailing list or blog. It has many different features and functions to give you a lot of versitility and control over how you promote your list. The developers of WPSubscribers have offered to give 3 of our readers a free triple license for the plugin, which will allow you to install the plugin on up to 3 different sites, plus free lifetime updates. This license normally sells for $47, and an unlimited license is also available for $97. WPSubscribers will allow you to integrate your opt-in code very easily, and then you can create several different types of forms to encourage signups. I've been testing the plugin and getting integrated with a MailChimp sign up form was simple. Just copy the form code provided by MailChimp (or another list manager like AWeber, GetResponse, etc.) and WPSubscribers will auto detect the fields and integrate.