J.W.
Contact your local hospital and see if they have a siblings' class. Even though you're not giving birth, the things that the 'big brothers and sisters' will learn and are exposed are so appropriate. It's fun, they and you will learn much, have activities to do at home. And because you're not pregnant, you will have the energy to involve him in the preparations for this new baby to your family. Have him help pick out receiving blankets, a couple of toys, some pj's, the mobile for the crib, pictures for the walls. At the same time, make some additions or changes to his room now that he's going to be a big brother. Put a box together of things he wants to pass on to the new baby now that he's the older brother. Have him create a picture book of his drawings or pictures he cut out of magazines that will be an 'welcome' to our family or instruction book for this new baby as to what you do and don't do, or what the baby can expect from him.
What an awesome time for all of you. There is no difference between this adoptive arrival or a biological birth, this baby is a part of all of you. Congratulations!!!