Congratulations from a mother of twins!
There is so much great advice in this thread. I'm impressed.
My experience with twins is a bit different than yours will be, as I had a 2 1/2 year old when my twins were born. I was used to dealing with one baby, then I had to learn how to deal with two.
I'm not gonna lie, having twins is tough. My best advice would be to help eachother out as much as possible. My ex-husband was next to no help when mine were born, and I was a miserable zombie for weeks. You're both going to be completely exhausted for awhile. Sleep when they sleep. When one gets up in the middle of the night to eat, get the other one up as well. If they're on the same schedule, it's so much easier. Oh, and if your wife is thinking about breastfeeding, please let her know that it is absolutely possible to do with twins - I breastfed mine for a year with no problems at all. Though, if she does breastfeed them, make sure that you get up in the middle of the night as well. There's nothing like trying to latch two babies on when you're all by yourself and bleary-eyed to boot.
Toddler years with my two have been ... well, hell (they're nearly four now). They're like little partners-in-crime. It's good that you're already thinking about anger management classes ... I've always been laid-back and easy going, not angry at all, but with these two, I often have to go outside, scream, and count to ten.
Also, be prepared for a rough pregnancy. It may go perfectly, and I hope that it does, but with twins, you just never know. I went into premature labor at 28 weeks and was put on strict bedrest (only getting up to go to the bathroom) for the remainder of my pregnancy (they were born at 36 weeks). Three weeks of that bedrest were spent in the hospital. It got to where the intake people in the ER knew me by name.
It's also good to prepare yourself for the idea that one or both of them may have to spend some time in the neonatal intensive care unit. When I was pregnant, we took a tour of the unit, and familiarized ourselves with all of the equipment so that it wasn't so scary. It turned out that one of mine - the littler one - did have to spend two weeks there for a collapsed lung.
Oh, my favorite twin book during my pregnancy was Having Twins by Elizabeth Noble.
Clickie It is (as I just found out) out of print, and many people appear not to like it, but it was the best one for me (and I read everything I could get my hands on).
Good luck to you both! You're definitely in for a ride ...