I am just running the production version and it works for me, but it is not very intuitive. You just start up Steam on both systems and go to your game library on the machine that will be the target system. When you click on the game, the Play button at the top of the game window will now have a down arrow. If you have the game on the target computer, the default option will be Play. If it is installed on another computer, but not the target system - the default option will be Stream.
If the game is installed on both computers, you can just click on the down arrow just to the right of the Play button and select Stream from (computer name).
Both systems have to have the same version of Steam installed (well, the patch version usually doesn't matter) and need to have the same Beta status setting. I don't know if it works if the computers are running different bit sizes, so that may be an issue - are both computers running 32 bit Windows or 64 bit Windows?
Also, the Steam server system has to be running Windows right now. The target system (client) can run Windows, Linux, or OS X.
I did have to add a Windows Firewall rule on both computers to make it work for me, but that was all I had to do.