Downloading SynCE is explained in SynceInstallation, but below are the different forms in which one can download SynCE:
Tarballs
Tarballs can be downloaded from the SourceForge project page: http://sourceforge.net/project/showfiles.php?group_id=30550
Packages
There are packages for Debian, Ubuntu, Fedora and Gentoo available. These are on their respective pages under SynceInstallation.
Subversion
The SynCE Subversion repository contains the bleeding-edge development work of the project.
https://synce.svn.sourceforge.net/svnroot/synce/ -- SVN repository
http://synce.svn.sourceforge.net/viewvc/synce/ -- Web-based repository viewer
Most modules can be "checked out" by executing:
svn co http://synce.svn.sourceforge.net/svnroot/synce/trunk/MODULENAME