chrisnorthwood

Pretty simple, really. Adds a new type of feed you can subscribe to. Simply 
add <code>?feed=json</code> to anywhere you get a normal feed to get it in JSON form 
(but with a cutdown version of events).
Version 1.1 added support for JSONP. To get a JSONP response instead of a 
normal JSON structure, simply add <code>jsonp=callbackName</code> to your query, where 
 callbackName is the name of the function to be wrapped with.
To use this with jQuery, you’ll want to do something like:
<pre><code>$.getJSON("http://example.com/feed/?feed=json&jsonp=?",
 function(data){
 console.debug(data[0].title); // print title of first item to firebug console
 });
});
</code></pre>
(thanks to Dan “Tack” Trudell)

JSON feed

Pretty simple, really. Adds a new type of feed you can subscribe to. Simply

petitnuage

This widget displays titles and links to the latest posts of a custom list of third party RSS feeds. It is useful for people who want to follow third party feeds updates on their own blog. It is also useful for blog networks where each blog can promote the latest posts of other blogs of the network.
Features list:
<ul>
<li>Customizable title.</li>
<li>Customizable introduction displayed before the recently updated feeds list.</li>
<li>Customizable number of maximum posts displayed from the same source.</li>
<li>Customizable number of maximum posts displayed in total.</li>
<li>Localized economy and market share news feeds supplied by default for immediate use (many thanks to <a href="http://www.labourseenaction.fr/" title="La bourse en action" rel="nofollow ugc">Bourse en ligne</a> for both English and French original news feeds).</li>
</ul>
Languages supported:
<ul>
<li>English</li>
<li>French</li>
</ul>
The plugin uses WordPress standard localization functions for localization. So, adding support for new languages (including the list of default RSS feeds, separated by “!”) should be straightforward.

Simple RSS Feeds Widget

This widget displays links to the latest posts of a custom list of third party RSS feeds.

JSON feed vs Simple RSS Feeds Widget