If I equip the porkchop and right click on the wolf, I eat it. If I left click, I beat him with it. If I drop it on the ground, he doesn't care.
How am I supposed to feed him?
edit: I did try both on SMP and on single player. Looks like I thought it wasn't working because apparently I arbitrarily decided that the raw ones healed the wolves more than the cooked ones, while they healed them so few that they didn't raise the tail.
I'll try again in SMP too as soon as I have the occasion, and let you know if it works there too.