Multiple people (two), have asked me how to have an icon next to their feed on movabletypo.net. The answer is in two parts, and only applies to people with Movable Type. People that already have an icon on movabletypo.net can look at these instructions to see how you can edit the icon that you currently have.
Part 1: Create an icon
Part 2: Edit your RSS 1.0 Index template to include this icon. This is slightly complicated, as you have to add text in three different places. I have included snippets of my template in the extended feed, highlighting the portions of text you need to add.
<?xml version="1.0" encoding="<$MTPublishCharset$>"?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
xmlns:admin="http://webns.net/mvcb/"
xmlns:image="http://purl.org/rss/1.0/modules/image/"
xmlns:cc="http://web.resource.org/cc/"
xmlns="http://purl.org/rss/1.0/">
<channel rdf:about="<$MTBlogURL$>">
<title><$MTBlogName encode_xml="1"$></title>
<link><$MTBlogURL$></link>
<image rdf:resource="http://userpic.livejournal.com/8972846/1507559" />
<description><$MTBlogDescription encode_xml="1"$></description>
<dc:language>en-us</dc:language>
...
<items>
<rdf:Seq><MTEntries lastn="15">
<rdf:li rdf:resource="<$MTEntryPermalink encode_xml="1"$>" />
</MTEntries></rdf:Seq>
</items>
</channel>
<image rdf:about="http://userpic.livejournal.com/8972846/1507559">
<url>http://userpic.livejournal.com/8972846/1507559</url>
<title>kwc</title>
<link>http://kwc.org/blog/</link>
<width>86</width>
<height>100</height>
</image>
<MTEntries lastn="15">
<item rdf:about="<$MTEntryPermalink encode_xml="1"$>">
...