im sure it will be on the pc. all of illusions games have been on the pc. and hell mafia was on the pc first and consoles 2nd so i wouldn't be to worried.
I'm hoping for a less linear approach in Mafia 2, but given what usually happens when games become non-linear, I'm worried they will be able to combine that with a story that matches the one in the original. Still, such a wonderfully conceived city and no meaningful way of freely exploring it was such a waste, if you ask me.