To get latest SVN of Twisted:
svn co svn://svn.twistedmatrix.com/svn/Twisted/trunk Twisted
You can replace "Twisted" with any other SVN module hosted on this server, assuming that the module has anonymous read-access set up.
Hosting of svn.twistedmatrix.com is graciously provided by Tummy.com, Ltd. We love you, tummy.
Art by J. "saph" Dockter. We love you too, saph.