The TCW package contains everything you need to run TCW. You only would want the source if you need to modify it.
The source is not documented, and some of the code is very old and confusing. However, you are welcome to ask questions
if you need to modify it, e.g. to add external data.
To build the TCW executable:
-TCW is distributed under the terms of the
GNU Public License,
and is freely available to all academic and non-profit users.
-Any publication, poster, or presentation that refers
to results obtained or displayed using TCW, please reference the
following paper, along with the publications for any program you
used within the TCW:
C. Soderlund, W. Nelson, M. Willer, and D. Gang (2013)
TCW: Transcriptome Computational Workbench PLoS ONE. Link