Preparing a toddler for a new sibling

Does anyone have any advice for preparing Porter for his new brother? Any neat things we should do for/with him to get him used to the idea? Any tips/tricks to making the transition from a 3 person family to a 4 person family after we bring Hudson home?

We talk to Porter all the time about his baby brother, how he'll come out of my tummy and he can help feed him etc. I ask him what he'll do if Hudson cries and he says "Want a sucky? Want a sucky?" HAHA!

He knows where Hudson's room is, knows we've bought him some clothes and that he has some toys in there. We've looked through Porter's old scrapbooks when he was a baby and told him that Baby Hudson is going to look like that when he comes out of mommy's tummy and that he'll come home with us and be a tiny baby just like Porter was.

I just am not so sure he understands, really. I mean, he's a smart kid, but I really don't think he can put the concept together that my huge stomach is going to produce a BABY and that he's going to come home and live with us. I'm afraid Porter is going to have a huge adjustment and I'm nervous that he'll react negatively to everything.

I'd like to make the transition as smooth as possible... what else can I do to help prepare Porter? What can we do when we're all home from the hospital to make things easier on Porter? I know we will definitely need to make sure we still try to spend one on one time with P-man as often as we can once we're home, but... anything else?