گناهکار

this plugin adds post custom fields in rss feed like this:
<pre><code><item>
...
<customfields>
<key1>value1</key1>
<key2>value2</key2>
...
</customfields>
...
</item>
</code></pre>

Custom fields in RSS

This plugin adds post custom fields in rss feed.

USAGE: 
use [cf] shortcode in your post content to show the custom field value without edit your theme files.
EXAMPLE: 
[cf]somekey[/cf] 
returns value of ‘somekey’ custom-filed.

Custom fields shortcode

Use custom fields as shortcode in post content without edit your theme files.

Custom fields in RSS vs Custom fields shortcode