It's coming June 10th to be precise, alongside a slew of updated content.
Games supporting the service out of the gates include PAIN, Wipeout HD and Super Stardust HD, the former of which we posted about yesterday. PAIN will require a ¥300 update in Japan, which we assume will translate here in the West too.
MotorStorm: Pacific Rift will also support the added dimension, but in demo form only for now. This will be packaged with new Bravia TVs when they go on sale this summer, presumably to give consumers a "taste".
Sony also reconfirmed that 3D Blu-Ray support will be implemented before the year's out, so consider your back covered.
Update @ 13:25 - Kotaku's reporting that this is for Japan only. Europe and North American dates are still to follow. Sorry @Jas_N!