There's lots of great advice here. I've got a 10-week old girl who I'm certain is the cutest, most wonderful little thing in the world. I'm assuming you're the dad (if you're the mom, I can't offer much).

Stuff to think about right now:

-Sleep deprivation starts early. Your wife is going to be uncomfortable as anything the last several months. She may toss and turn a lot at night. Plan accordingly.

-If there is anything you've been wanting to get done, do it now. I had been putting off copying my old Amiga hard drive to preserve my childhood computer for 10 years. I narrowly got that done before the baby arrived.

-Make some meals you can easily freeze so you don't have to cook if you don't want to. You'll need this in the first few days as well as much later when you and/or mom go back to work. Cooking is a royal pain with a really little baby.

Stuff to think about after the baby arrives:

-Plan on not getting any sleep and being entirely unproductive while awake (you are taking several weeks off work right?) the first few months.

-Expect that while awake, you will have zero time to yourself. Use the time you do have wisely, frittering it away on Facebook is probably a bad idea.

-Expect the first night home to be unreal. My wife is a pediatrician and I thought that would prepare us. Boy was I wrong. We were still two bumbling clueless parents. Best thing we learned that night is division of labor: one sleeps while the other is awake with the baby. Otherwise, you are both going to be completely exhausted instead of a manageable "really tired".

-A smartphone is a huge help with a little one. I read HN at night a lot when my daughter is drifting off to sleep in my arms but not fully asleep. I do it primarily to keep myself from falling asleep while holding her. It's easy to hold in one hand (vs. a laptop or iPad).

-Babies love white noise. They find it incredibly soothing. Get a white noise generator of some kind. We have a 99-cent iPhone app on our phones that we use daily. My daughter loves "air conditioner" mode. She often fights sleep and squirms around a lot. White noise and a pacifier put her into a deep, restful slumber.

-Babies get cranky for a variety of reasons you will never know. Your inner geek is going to want to find reasons for things and understand "the system". Resist this, it's futile 50% of the time. Instead, try random things: change the diaper, change position, walk around, sit them upright, lay them down, etc... It's good to have a bunch of stuff to run through. Sometimes, a screaming baby just needs his or her mom though, don't forget that.

-Babies like to be with you. Get a bouncer chair so you don't have to hold them all the time and they can watch you as you steal 5 minutes to post photos online. Get one with a vibration mode. They find it soothing and can nap for quite a while there.

-Plan on doing lots of laundry. Babies mess up their clothes and yours all the time. Make sure you have a basin or utility sink where you can soak clothing with detergent to get poop out of it before washing in the machine. We discovered Oxi Free (doesn't have any perfumes as opposed to regular Oxi) takes poop out really well and doesn't damage colors.

-Take tons of photos, they change a lot very quickly.

-Efficiency is key. Look for places to reduce labor. Are you always carrying pacifiers around the house? Leave one in each room. Spending lots of time washing bottles? Get a dishwasher rack that holds them. No time to clean your house? Get a cleaning person to come in and give it a once-over. Just as with a startup, sometimes it's better to trade money for time.

-Mom needs you more than you realize. Help her out. The biggest thing you can do is to suck it up, tell her to get some sleep and take the baby for a while. Yeah, you're exhausted, but babies need moms who aren't basket-cases. You'll survive.

-Talk to your pediatrician about any concerns you have, no matter how silly. They hear the same things a lot. A good one will give you excellent advice, even about things that aren't strictly "medical".

Best of luck to you. It's a life-changing experience and one of the happiest times in your entire life.