Well, it turns out one of my favorites - a wordless book by Annie Kubler - no longer exists? and has been re-done... It could still be just as good, or I have no idea. The illustrations are totally different.
My New Baby is the book, but now it is by someone else and looks totally different (and I know that I sound crazy and that this is just a different book, but it isn't - that was the title and the cover art was of the same thing, just a different style).
On Mother's Lap is a good one.
Hello Baby is for older kids but does show the baby developing inside, which is neat.
We have a baby
is the one I mentioned before, it's probably my toddler favorite.
On the off chance you speak a nordic language,
Hej, Lillebror! is a totally AP great book in Swedish. Bokus.com is where I got it.
This book just looks really cute
, but I just stumbled upon it when getting the amazon links for you, so I can't recommend it or not.
Tjej
ETA: I thought of another thing we did before DS arrived that I think made a big difference - we switched things around so DD's bedtime routine was with DH. That way she didn't feel gypped at bedtime when I was nursing and settling the baby - it was already what she expected so it wasn't the baby's fault at all.
Oh, and speaking of fault, I was careful not to "blame" the baby for anything - like I wouldn't say "I can't help you now because I'm nursing the baby". I'd either help her or I'd say "I'll help you in a minute or two with that, would you like to read this book with me now?"