Mike–

Omeka also has RSS feeds for search results out of the box, which could be another option for smaller institutions. Just add &output=rss2 to the query string of the search results URL (e.g. http://example.com/items/browse?search=foobar&output=rss2). It also works with any of the search criteria, so you can do this with a more complex search. For instance http://example.com/items/browse?type=Document&tag=gorbachev,stalin&output=rss2 would give you the RSS feed for all Documents that were tagged both gorbachev and stalin. Again pretty similar to Perry and Eric’s examples. We’re also talking about implementing ATOM.

Tom