Henry is four months old now. He is getting better about sleeping through the night, but it isn't perfect. Sleep now. Like wizard said, take your wife out, go see a movie, even if its a bad one. Expect to get fluids in your mouth- you've got a slight advantage there with a girl, you really only need to worry about the spit up. Learn to mix up saline solution - it helps break up baby mucus and makes them sound less like tiny warthogs. Be there, like was said before. For the first few months remember that the baby needs mom a lot more than she needs you, but mom really needs you during that time. If you arent one to cook, start getting some quick recipies under your belt now.
Henry just learned to roll over this weekend. Also learned squealing is super fun - so that's nice...