This article describes how one would download the sources.
Please note, you must write us at ewedevteam@? to request permission stating who, why and how you would use the sources in-order to download the sources. From there, we will give you access to our SVN server.
Ecopath6: ?http://sources.ecopath.org/svn/Ecopath/trunk/Ecopath6
Click OK and enter your username and password
Ecopath5: ?http://sources.ecopath.org/svn/Ecopath/trunk/Ecopath5
A WinCVS alternative to SVN would be ?RapidSVN. A Visual Studio Integration to SVN would be ?ankhsvn.