We have twin boys, I was lucky enough to take time off to help my wife. It's fine when they are in baskets, once they start crawling the fun begins.
Sign up for everything from pampers, food companies, etc., it can really make a difference in costs, free diapers is free diapers. There are lots of twins clubs/meetings for expectant parents if you want, as you already have a child it's easier for you, get a breast feeding pillow and comfy chair for your wife.
Start getting used to buying two of everything as it will last until they are big
Good luck and enjoy it, it is a true blessing.