Note: To use the binary NTW GTK Client on Windows, you'll need to download the GTK library if you don't already have it. This library is available from the gimp-win installer project.
You don't need to download the Gimp, just GTK for your version of Windows. If you'd like to compile NTW on Windows, instructions are available here.
Source Code - GTK Client and C Server
This is the reference implementation of NTW, written in C.
Windows Binary - GTK Client
This is binary .exe installer. You must have the GTK library installed.
Windows Binary - C Server
This is the latest NTW Server for windows. This is for demo purposes only, as it can only serve a single client.
Source Code - Lisp Server
The Common Lisp version of the NTW server works with either SBCL or CMUCL, and handles multiple clients (using serve-event). Most of the widgets are implemented. It's also possible to use this server interactively with the GTK client. See the flash demo for an example.
Source Code - Java Server
The Java Server is old but still functional. We're looking for maintainers for it.