Mailbag lets you quickly and easily add MailChimp or Campaign Monitor email forms to your posts or pages with a shortcode.
MailChimp settings tab. Enter your API keys and select a subscription list.
Campaign Monitor settings tab. Enter your API keys and select a subscription list.
General settings tab. Enable or disable form styles.
Usage tab. Find out where to find your API keys and how to use Mailbag.
Add a MailChimp subscription form to your post or page with the [mailbag_mailchimp] shortcode.
Add a Campaign Monitor subscription form to your post or page with the [mailbag_campaign_monitor] shortcode.
You can disable styling for the forms, if you'd rather inherit styles from your current theme. This is a theme with the Mailbag styles disabled.
This is an example of Mailbag in use with Transmit WordPress theme, with styles enabled.