To download Jade, click here.
Once you have the file on your machine you can run it to install Jade. For the program folder, choose a folder name without any space characters in it (please don't choose Program Files). Once Jade is installed on your computer, you can run it either through the Start menu or by running Jade.exe found in the installation folder.
To download the source code, click here.
The project is written by Yair Harel. It is compiled using Visual Cafe 4.0a Standard Edition (that can be freely downloaded from WebGain. The installation program is Install Anywhere Now (that can be freely downloaded from ZeroG.