This is the info from Apple on updating a podcast:
If you need to request that iTunes update information about your podcast immediately, you can ping the iTunes server in one of two ways: using an XML POST or by entering a URL in a browser.
The XML POST should be addressed to
phobos.apple.com/WebObjects/MZFinance.woa/wa/pingPodcast and formatted as follows:
<?xml version="1.0"?>
<methodCall>
<methodName>weblogUpdates.ping</methodName>
<params>
<param>
<value>PODCAST_NAME</value>
</param>
<param>
<value>
FEEDURL/</value>
</param>
</params>
</methodCall>
where PODCAST_NAME is the title of the podcast, exactly as it appears in the <title> tag, and FEEDURL is your podcast feed URL.
You can also ping the iTunes server to update your podcast information by entering the following URL into a browser:
phobos.apple.com/WebObjects/MZFinance.wo...ingPodcast?id=FEEDID
where FEEDID is your iTunes podcast numeric ID. You can also use:
phobos.apple.com/WebObjects/MZFinance.wo...edURL=http://FEEDURL
where FEEDURL is the url for your feed.
Regardless of the ping method you use, iTunes will return an HTTP 200 code.
I would think that method one is doable from withing the /site/helpers/writexml.php helper function since we will know both the podcast title and feed url from within JBS. I'll enter it as a feature request for 6.3
Tom