Next year sometime, once the GECK is released for Pc and people can start making mods which will be compatible with whatever distribution system Bethesda will use.

HOWEVER, I wasn't aware Sony and Bethesda had confirmed mods for PS3 yet. We only have them confirmed for XboxOne so far. (That I've seen)

PC Mods are coming to Xbox One first, but they are planned for PlayStation 4.

Smiles and nods..