Vienna is a freeware, open source RSS/Atom newsreader for the Mac OS X.
BS Editor: Vienna is a freeware, open source RSS/Atom NewsReader for the Mac OS X operating system. It provides features comparable to commercial newsreaders, but both it and the source code are freely available for download.
A summary of some of its features:
-Subscribe to Atom/RSS news feeds and podcasts.
-Simple and intuitive user interface with customisable toolbar.
-Built-in tabbed browser.
-Global search of all retrieved articles.
-Automatic detection of newsfeeds on web pages.
-SMART folders for organising related feed articles.
-Custom article display styles.
-Three separate reading layouts.
-Blogging integration.
-Support for downloading enclosures in articles
-Filter the displayed articles.
-Manual reordering of the subscription list.
-Full AppleScript support.
-Localised into several languages. you can free download Vienna 2.2.2 now.