Apparently they're still working those things out. I'm sure you can probably play multiplayer games for free like how it is now. I read somewhere that they're thinking of having a few options for people as far as an 'online subscription service' goes. Something about having 'Silver', 'Gold', and 'Platinum' services. We'll have to wait probably until E3 for more details on that.
It would be a very bad PR move on Sony's part to introduce online interaction on a subscription basis. They've offered it free for the last 10+ years. Imagine the fallout. Many people who dedicate their gaming to a single console would definitely think about jumping ship.
I would hazard a guess and say, yes.