There's loads of info on this forum for relocating to Germany in general.
If one of you has a job lined up, the company could probably be useful in at least the basic relocation. Some of the specific pain in the ass issues my firm talked to me about were:
-Obtaining Permits (residence & living permits)
-Obtaining Proper Housing (lots of places in Munich don't come with kitchens so be sure to ask what the deal is in Berlin)
-Private vs. Public Health Insurance
-Setting up a Bank Account
-International Shipping of Household Goods...btw: some thread or another ago there was talk about possibly having to register new kids BORN in Germany but I don't know what needs to be done with "imports".
If you don't have company assistance, no worries, this site has loads of info. Just do a keyword search and you'll get heaps of stuff.
Alternatively I found loads of helpful books and sites. Expatica has a dedicated
Relocation Site (to Germany) that you might find useful.
Now, not that I have any children but since I am one on most days some other things that you might want to look into are baby and health needs.
-Specific formulas, medicines (infants or adults) etc aren't always available here so you might want to pack extras of those to get you through the first few months. You'll be able to get everything you need there - just might be under different labels. If all else fails, there's probably a
Walmart or two around there.
-Getting Your Kiddie Dr. The english speaking consulates here have a list of dr's on their websites. I assume you'd be able to find loads of similar help in Berlin. However, I understand some of the lists posted in Munich are crap, so I'd also say that as soon as you hit the ground start calling around for a pediatrician...it might take you a while to find a good one you like. Nothing worse than having some sort of medical issue pop up and not having anyone to call.
Last but not least, you'd be doing yourself a big favour if you can squeeze time in your day to take a german course or at least an DIY dvd programme. Might not be able to have a chat but at least you'll have the basics