All Recent Changes pages can become feeds simply by adding
?action=rss to the end of the URL, and subscribing to that address in your news aggregator. To make a custom feed, create a new page and fill it with a WikiTrail of the pages that you want updates from. Then add
?action=rss to the end of its URL, and subscribe to that address in your news aggregator.
Please see PmWiki.RSS to get more information about what feeds are and how they can make your life easier.