The online version of the freerouter tool is no longer available ( http://www.freerouting.net/ )

The source is now available and to get the ‘Export a Specctra Design and Launch FreeRoute’ button active in PCBNew on OS X, you need to download the Freerouting.jar file. Since the Kicad source code looks for a file named freeroute.jar you’ll need to rename your downloaded file this. Place your renamed file in /Applications/Kicad/kicad.app/Contents/MacOS/ and now when you are in PCBNew and click ‘Tools -> Freeroute’ the ‘Export a Specctra Design and Launch FreeRoute’  button will be active.