I used SimplePie to display Blogger atom feeds in Media Wiki (using the ancient 1.5.2 version). Here's an example:
To add another feed, all you need to do is edit a page and add this:
(Replacing chembiogrid's atom.xml with the alternative feed URL).
More info is here: http://simplepie.org/. It is as easy as advertised. See particularly here: http://simplepie.org/docs/plugins/mediawiki. Or just google "simplepie mediawiki".
Avoid Magpie RSS. I spent the whole afternoon trying to get it to work with Atom with no luck. SimplePie worked in about 5 minutes.