I think there are several possibilites for displaying the icons in the lists, just depends on what is easier. Starting with my least favourite choice:

• Centralised at the top of the page as part of a header band
• In a little block with feed logo, url and some stats like latest refresh.
• A smaller icon at the bottom of each entry, along with date and time of publication if available.

I think the last one works best if your considering displaying content from several sources in one list. You could even link the icon to each feeds dedicated list.