With Word it is easy to save the file to PDF. Since Office 2010, Word has a built-in Save as PDF function, for version 2007 you can download a plugin from Microsoft website for free. With older versions, you can install one of the various free PDF printers that you can find online.
Once you have the PDF file, there are many programs that convert from PDF to DJVU. For example, the command line tool pdf2djvu available for download here. If you prefer a graphical interface, you can use PDF to DJVU GUI.
EDIT How to use pdf2djvu from the command line
First, download the zip file containing the program files and extract them to some folder. Take note of the path where you extracted them to. Open a command prompt and navigate to the folder where you extracted the files using the command (I use an example path, which you must replace with your specific path)
cd C:\pdf2djvu-0.7.14 Now use the following command
pdf2djvu.exe pdf_file_path.pdf -o outputfile.djvu where pdf_file_path.pdf is the complete path to the PDF file (e.g. "C:\Users\John Doe\Documents\pdf_file.pdf", double quotes if your path includes spaces) and outputfile.djvu is the output file. If you don't specify a path then the file will be created in the program folder. The program will report its progress.
Notice that you can set options for the djvu file such as resolution, page size etc.
If you have a large number of files to convert we can work on an automated script.