Aaron Butacov

It adds a simple month-by-month calendar that shows all the months you have future posts for (and the current month no matter what), it highlights the days you have posts for, and as an added bonus if you click a day, the Post Timestamp boxes change to that day, month and year.
Also includes a widget so you can show users what upcoming posts you have on your website.
If you want to ad a widget to your dashboard, uncomment the line <code>add_action('wp_dashboard_setup', 'fpc_setup_dashboard_widget');</code> in the future_calendar.php file.

Future Posts Calendar

This plugin adds a monthly calendar that shows all the dates you have future posts.

Ron Zvagelsky

Monthly grid view calendar widget highlighting archived and/or future posts.
Additional Features:
<ul>
<li>Popup details for each date with posts</li>
<li>Optional details include post author and comment count.</li>
<li>Ability to show posts by post type, category, specific taxonomy and/or term</li>
</ul>
<a href="http://presshive.com/plugins/wordpress-blog-post-calendar-plugin" rel="nofollow ugc">For more information or to request additional features, please visit the plugin page</a>

Blog Post Calendar Widget

The Blog Posts Calendar Widget allows you to display your archived or future posts in a calendar as a sidebar widget.

Future Posts Calendar vs Blog Post Calendar Widget