INN (InterNetNews) is an extremely flexible and configurable Usenet / netnews news server. It supports accepting articles via either NNTP connections or via UUCP, as well as serving out articles to reading clients via NNTP. It supports multiple different ways of sending outgoing articles to other hosts, as well as multiple different storage mechanisms for articles and article overview information via internal APIs. Compared to other news servers, INN is more complicated with a steeper learning curve, but is extremely flexible and configurable, comes with a large suite of supporting programs, and supports embedded filters in either Perl or Python.
MCNTP is a proctocol and an implementation of that protocol to exchange NetNews articles between servers in a bandwidth-friendly way. The package contains the complete suite of tools and is ready to run with a news server that uses the classical spool concept (such as INN 1.x). As of 1.2, there is also support for the INN 2.x storage API.
Papercut is a multi-threaded NNTP server written in Python. Its main objective is to integrate existing Web-based message board software (Phorum is one of the supported ones) with a Usenet front-end. However, its extensibility enables developers to write their own containers for the storage of the Usenet articles (messages). That means that the code is extensible enough that you could write new containers to integrate the news server with other Web message board projects or even other ways to store the messages.