A few days a go, registrations for Steam's new In-House Streaming service kicked off. As per usual, the "registration" part of this is simply to join the new service's Steam group.

Valve says that the beta will be open to external beta testers "later this year." As you might gather from the name, the In-Home Streaming service will allow you to stream your Steam games from one PC to another on the same network.
Steam In-Home Streaming is a feature that will allow people to stream games from one computer to another anywhere in their house.

This feature will be available for beta testing later this year. Beta participants will be randomly selected from members of this group, so join, have fun, and stay tuned for more details!

This is undoubtedly an important step towards a big feature within SteamOS, which is slated to arrive with the Steam Machine next year.