keksus

This plugin allows you send messages to email from a page, post or from any other location that you specify in template. It can be used as a shortcode or a widget. 
Has a admin settings page where you can change the names of fields, enable or disable captcha, add custom CSS code.
<h3>Live Demo</h3>
<ul>
<li><a href="http://keksus.com/ae.html" rel="nofollow ugc">http://keksus.com/ae.html</a></li>
</ul>

Ajax Message

SpeakPipe

With SpeakPipe you can receive voice messages from your audience directly on your website. Installing SpeakPipe on a website is easy and takes less than a minute. Visitors don’t need a SpeakPipe account to send you voicemail. A message can be sent with just a few clicks without typing anything. 
Learn more at http://www.speakpipe.com/tour
This plugin allows site owners to easily integrate their SpeakPipe code into their WordPress site without having to change any source code or theme files. 
Please note that all your voice messages and data are stored on speakpipe.com, for more information please see our Privacy Policy at http://www.speakpipe.com/privacy
Feel free to contact us with any questions at http://www.speakpipe.com/contact or via email support@speakpipe.com

SpeakPipe – Voicemail for Websites

Allows your customers, blog readers, podcast listeners and fans to send you voice messages right from a browser without any phone calls.

Ajax Message vs SpeakPipe – Voicemail for Websites