these instructions to begin spreading the Steam love.
Valve, a busy bee at the moment, unveiled Steam Family Sharing earlier this month. The service allows Steam members to share their libraries with up to 10 other users, each one able to earn their own achievements and save their own progress. Each Steam library can only be accessed by one user at a time, the owner having priority access at all times.
There's no timeline for when the full program will run out for all, but in the meantime you can check out the Family Sharing FAQ for a fuller list of the can-dos and cannots.