<p>I have been attempting to write some routines to read RSS and ATOM feeds using the new routines available in System.ServiceModel.Syndication, but unfortunately the Rss20FeedFormatter bombs out on about half the feeds I try with the following exception:</p>

<blockquote>
<pre><code>An error was encountered when parsing a DateTime value in the XML.
</code></pre>
</blockquote>

<p>This seems to occur whenever the RSS feed expresses the publish date in the following format:</p>

<blockquote>
  <p>Thu, 16 Oct 08 14:23:26 -0700</p>
</blockquote>

<p>If the feed expresses the publish date as GMT, things go fine:</p>

<blockquote>
  <p>Thu, 16 Oct 08 21:23:26 GMT</p>
</blockquote>

<p>If there's some way to work around this  with XMLReaderSettings, I have not found it.  Can anyone assist?</p>

Interesting. It would looks like the datetime formatting is not one of the ones naturally expected by the datetime parser. After looking at the feed classes it does not look like you can inject in your own formatting convention for the parser and they it likely uses a specific scheme for validating the feel.
You may be able to change how the datetime parser behaves by modifying the
culture
. I have never done it before so I can't say for sure it would work.
Another solution night be to first transform the feed you are trying to read. Likely not the greatest but it could get you around the issue.
Good luck.