There is a prototype of the news infrastructure and an NNTP server that uses it available in CVS. To make your node run the NNTP server, add the following lines to your .freenetrc:
services.nntp.class=eof.nntp.NntpHandlerServlet
services.nntp.port=1119
services.nntp.config=.eof-nntprc

Create the file .eof-nntprc if you want to pass any special parameters to the NNTP server (such as the port that your node is running on).

To configure your news reader, just tell it that the address of the news server is localhost:1119. So news readers require that the news server be on the default port. Such news readers are dumb. You can change the port parameter in your .freenetrc file to 119 if you have this problem. However, that will require you to run your node as root, which seems like a generally bad idea.