Subversion WebGUI is no longer hosted in Subversion, so please see the Git page for updated information.
Using SVK with Subversion "SVK is a decentralized version control system built with the robust Subversion filesystem. It supports repository mirroring, disconnected operation, history-sensitive merging, and integrates with other version control systems, as well as popular visual merge tools." -- see http://svk.bestpractical.com