Bring a blanket or something with "puppy smell" home and let the cats get used to it. When you finally bring home the pup (lucky you!!!) introduce him SLOWLY to both your house AND the cats. I would recommend to keep the cats away and introduce the house, room by room, first, then introduce the cats in a controlled way. Don't just let him loose on the kitties or the kitties onto him.
This is a lot for BOTH kinds of animals, but since the cats were there first, I would allow them to come up to the dog while your holding him to sniff, look, ignore, whatever they choose.
You should also allow the cats to have a "safe" place. Maybe upstairs, or the basement, something they can get to whenever they want to, where the dog is not allowed to go. Since the pup will be doing the chasing more than likely, the kitties need a safe place to retreat to. Good luck!!