First of all, Congrats!!!
My dogs were very crazy about my tummy, they wanted to sleep on it (with their heads) and talked with the baby (they putt their head on my tummy and waited for the baby to react, if he didn't react they softly moved with their heads to ask for a reaction.. and he always did..
I agree with Querus, she already told a lot of thing we also took care of.
We made Ryan's room long before my due date, and bought all the stuff also long before that date.
It's important the dogs get the same attention as always.
And when the baby arrives, let him see the little one and let him be apart of all the fun.
Don't let the dog wait for attention when you are busy with the baby, also give him attention when you are busy with the baby.
That way he won't think "I don't like the baby beause when the baby is aroun I won't get my attention"
And we told our guests "don't be running to the baby, stop by our other baby's first!
Amost every guest brought snacks for the dogs.. they said "well… the other kids need a present too for this great party!!! "