For the first few days, he didn't acknowledge her anymore than the occasional "baby!" when he noticed her in the room. He was otherwise distracted with family members staying with us. We got him to call her "sissy" and he liked that better I think.
After our guests left and we had the apartment to ourselves, Talmage realized that the baby was here to stay. He became more interested in talking to her and touching her head and such. When I put her in the swing, he would sit on the floor and watch her, sometimes rocking the swing himself. It was very cute :]
Now when he wakes up in the morning, he runs into the living room, looks around and asks for "baby sissy". When she naps in her crib he tries to climb onto our bed so he can get a peek at her. And this morning I used a bulb syringe on her nose to get the snot out, but he thought I was hurting her and told me "No no no!"
He loves to give her stuff, too.
By the end of the bath, she wasn't crying anymore- just making funny faces.
Every once in a while I'll let him hold her. He thinks her soft sleepy squishy self is pretty interesting. (And if she happens to sneeze or cough while he's holding her, he thinks that is HILARIOUS. haha!)