Can I get him to knock this off? Teach him that it hurts?
It's like he doesn't realize he is big and can hurt me....
Yes, you can teach him not to do this! I'd start with not allowing his feet on you at all, if he puts them on you, all fun and games stop immediately. Then add some kind of rewards for when he doesn't put his feet on you at times when he normally might.
Check on google for methods of teaching body (especially foot) awareness for dogs (often used for agility). The more aware of his feet he is, the less likely he is to be putting them where they shouldn't be. Most places seem to focus on rear foot awareness (like Full-Body Awareness in Agility
), but this can also apply to front feet and help you work with him so he isn't slapping his big paws all over you.
Also important is working with your dog now on control and calmness so that when you do introduce the baby (ALWAYS ALWAYS SUPERVISED) your dog won't get hyped up over the strange squeaky thing that has suddenly invaded his home. If you have a chance to meet up with other parents that have young babies so he is exposed to them, that might be helpful as well.
Here are a couple links that may give you more information:
Baby Safety Around Dogs | Prepare the family dog for life with a baby
Dogs and Babies | Learning to Live Happily Ever After
(I love this one, it has a ton of info)
By the way, you may get advice on here that is very blunt, to the point of seeming rude, but there are a ton of really knowledgeable people who you can really learn some neat stuff from. Let answers you don't care for roll off your back, and take away the things you can use, and you'll probably find this forum is one of the most awesome places around.