dmallon

The Post To Sidebar plugin makes it easy to display post content in the sidebar areas of your site. Once the widget is activated, a multi-select dropdown of all your published pages appears on post editing screens. Select the pages upon which you want the post to be displayed and the post will appear on those pages.
There are options to hide the post title in the output and to show the content as an excerpt.

Post To Sidebar

A WordPress plugin/widget that gives you the ability to put content (posts and custom post types) in your sidebar.

stiwahn

Simple Page to Sidebar is a plugin that adds a widget which enables you to display any page content in your sidebars. Just choose any page using the dropdown in the widget area. Also unpublished or private pages content can be shown.
<h4>Features</h4>
<ul>
<li>No posts, just pages.</li>
<li>Internationalized for english and german.</li>
</ul>

Simple Page to Sidebar

Simple Page to Sidebar lets you simply add page content to a sidebar. No more, no less.

Post To Sidebar vs Simple Page to Sidebar