A while back, I wrote up a how-to on some mods I made to my ECM Giotto espresso machine. After giving it some break-in time, I finally wrote up my cheap plumbed in espresso trick. Plumbing kits use a $50 solenoid that requires special plumbing. My version uses a $12 fridge solenoid, easily adds on to my previous mods, and only requires some tubing size adaptation.
http://www.hackaday.com/2008/03/16/plumb-in-your-espresso-machine-cheap/