Joost de Valk

Adds a simple to use [rss] shortcode with a couple of options:
<ul>
<li>feed, to put in the feed URL</li>
<li>num, to specify the number of items to show, defaults to 5</li>
<li>excerpt (true|false), whether to show an excerpt or not, defaults to true</li>
<li>target (defaults to none), to make links open in a new page (might break your html validity if under a strict doctype)</li>
</ul>
Example use:
[rss feed=”http://yoast.com/feed/” num=”10″ excerpt=”false”]
Or:
[rss feed=”http://yoast.com/feed/” num=”5″ excerpt=”true” target=”_blank”]
<ul>
<li>Find out more about the <a href="http://yoast.com/wordpress/rss-shortcode/" rel="nofollow ugc">RSS Shortcode</a> plugin</li>
<li>Check out the other <a href="http://yoast.com/wordpress/" rel="nofollow ugc">WordPress plugins</a> by the author</li>
</ul>

RSS Shortcode

Simple plugin to show RSS feeds in posts and pages using a shortcode.

WordPress.org

RSS Importer

Causes errors with current versions of both PHP and WordPress

RSS Shortcode vs RSS Importer