Sony has just taken the veil off PlayStation Now streaming service which will allow you to stream popular and classic games from their PS3 library. This will initially only be available for the PS3 and PS4, however it will soon come to the PS Vita as well.
You will be allowed to rent specific games or submit to a subscription service to explore many other games. PS Now will also sync across devices, which will allow you to pick up where you left off. The service is also coming to the 2014 Sony BRAVIA lineup and to other Internet-connected devices soon.
PS Now will begin a Beta program in the US at the end of January with an expected full roll-out in the US this summer.