rep-XMMS is a rep module allowing you to remotely control XMMS.
Rep XMMS provides access to the XMMS remote control interface from within the rep interpreter. In addition a modules is provided to give access to the XMMS commands from within the sawfish window manager.
Once you have installed the plugin, you can (require 'xmms.remote) from within a rep session which gives you access to the module. More usefully you can put (require 'xmms.command) in ~/.sawfishrc (or ~/.sawfish/rc if you prefer) and then configure your key-bindings from within the sawfish UI.