Smilla .NET Communication Library provides support for NNTP protocol. It is written in C# and doesn't use any 3rd-party components. It's distributed under the terms of the GNU Lesser General Public License.   Code: ASP.NET v1.0 & C#

TCP wrapper class for the Network News Transfer Protocol (NNTP), written in C# for the Microsoft .Net Framework, allows developers to easily add newsreading features to their windows and web applications.   Code: ASP.NET v1.0