aubng is a Usenet binary decoder implemented entirely in Perl5. It has a boatload of features, including: decoding of uuencoded and Base64 postings, assembling multi-part postings, remembering already seen binaries in a newsrc file, saving metadata about news postings, smart renaming of binaries with the same name, removal of duplicate binaries, and easy XML-based configuration. Aubng also features an extensible handler architecture, so it is easy to add your own features.
NewsLib is a library of Perl modules for managing Network News services. It's meant to be used for code-reuse and sharing when writing news-based applications. It includes Net::NNTP::Client (simulates a news client), Net::NNTP::Proxy (a proxying news server), and News::NNTPAuth (NNTP authentication).
pgpmoose is a program that cancels invald messages from moderated Usenet groups. All messages to a specific group are assumed to have a PGP signature added at injection by the newsgroup moderator; if no such signature exists, or if the signature is invalid for the stated moderator of the group, then the message is assumed to be invalid. This program takes care of actually issuing the cancels for those messages.
NewsOutlook is a tool that aims to improve the signal to noise ratio of Usenet newsgroups and syndication feeds (RSS and Atom) by selecting only useful news. It consists of two modules: a Web-based configuration front-end and a server daemon. It uses the HTML::Mason framework and stores data in a MySQL database.