The process involving physically streaming a game from one computer to another on your local home network has entered open beta, per an announcement in the Steam “homestream” group. This allows you to fire up a graphically intensive game on a gaming computer, and continue playing it on a laptop whilst lying in bed, or on a Steam Machine on the couch. The process works by translating the controls you input on the local platform, and sending them, ideally in a lag-free environment, to the host computer, without having to bother with rendering anything aside from the video feed on your local screen. 

Steam streaming is nowhere near feature complete, as the “issues” list underneath the news prove, without support for Windows XP machines, and neither Mac nor Linux supported either. Furthermore, surround sound isn't supported, the sound instead coming out in stereo, and older, single/dual core machines. Those with graphics processors that don't support the H264 video codec may also find themselves out of luck, at least, for now. 

Regardless, for those looking to be a bit more mobile with their gaming, provided they can meet the necessary requirements, may very well find this useful. Users can sign up via opting in to the latest client beta, and downloading the patch, as of April 30th. With said beta long overdue, at the very least, it looks as though Valve is looking to expand the offering that Steam Machines can provide.