In an rss feed, the output of the php script generating the feed is xml, rss is an xml format
<?xml version="1.0" encoding="ISO-8859-1"?>
<rss version="2.0">
<channel>
<title>CBC | Top Stories News</title>
<link>http://www.cbc.ca/news/?ref=rss</link>
<description>FOR PERSONAL USE ONLY</description>
<language>en-ca</language>
<lastBuildDate>Mon, 31 Aug 2009 15:25:52 EDT</lastBuildDate>
<copyright>Copyright: (C) Canadian Broadcasting Corporation, http://www.cbc.ca/aboutcbc/discover/termsofuse.html#Rss</copyright>
<docs>http://www.cbc.ca/rss/</docs>
<!-- /* snipped */ -->
</channel>
</rss> so rss2html any of the php addins like magpierss to parse rss will likely work, even though the filenam is .php
php scripts can output images .pdf html csv .doc .xml and a bunch of other formats on execution
there is a good likelyhood that you could point the feedreader to the php script as source
Google does index pages generated by feed2Html , (am using it to add feeds from local newspapers) they show up in site:mysite.com searches