IcculusNews is a Perl-based daemon that sits on port 263 (by default). It is used for many sites, including icculus.org itself. IcculusNews can output headlines streams. It also has a GTK+(2) interface (screenshot), and a library for other client access. There is also a php/web-based interface integrated without libinews.
You can check out IcculusNews from Mercurial via these simple instructions:hg clone http://hg.icculus.org/icculus/icculusnews/
IcculusNews is currently lacking in documentation, however, the protocol is documented in protocol.txt
You can see the web-based Mercurial interface here
You can subscribe to the mailing list for IcculusNews by sending a blank e-mail to: email@example.com
You can file bugs against IcculusNews in bugzilla