Sony has said that PSN games for the PS3 will not be compatible with the PS4, but they never said it would be impossible to port these games. Sony is in fact porting over four PSN favorites to be available around the PS4's launch in November: flOw, Flower, Escape Plan, and Sound Shapes.
Flower and Sound Shapes will be available on launch day, November 15th, for both the Vita and the PS4. FlOw and Escape Plan will be available for both the Vita and PS4 on the 29th.
The best part? If you've already bought these games for the PS3 or Vita, they will be automatically available to you at no extra cost for ALL compatible systems.
All they need to do now is port Journey over to the Vita and PS4. I cannot wait to play both flOw and Flower on my Vita.