Update: Sony is not willing to comment on the subscription model at this time, and would not tell me if PlayStation Plus users will automatically gain access.
"We have nothing to announce at this point in time," said a company spokesperson.
Sony has previously teased a streaming gaming service using the Gaikai technology it acquired in 2012, and now we know what the company has planned. It's called PlayStation Now, and it was just announced at CES.
(Wait, when did CES become relevant for games again?)
PlayStation Now is a subscription-based service (it's unclear if PlayStation Plus subscribers will have to pay an additional fee, but it seems likely) that will give players access to PlayStation 1, PlayStation 2, and PlayStation 3 games. Besides streaming games to PlayStation 4 and Vita, it will also stream to non-PlayStation devices, including phones and tablets.
In addition to a subscription, players will be able to rent games on a per title basis.
PlayStation Now will enter into beta in the United States this month, and rolls out everywhere this summer.