H.D.
Hey Kevin. =)
Don't be nervous! It's a wonderful adventure! I spent 4 years in Nurenberg and LOVED it! My kids were 1 and 3 when we first went there and my oldest was school age when we left. This was 20 years ago so I can't speak to the level of education but I can say that for us, and our kids, it was an amazing experience! Even if the schools aren't very good (in my experience military schools are just fine!) you can fill in the gaps. Encourage the kids to read (most posts have libraries), buy games that challenge their math skills (card games) and spelling (Scrabble). Draw a one hour distance in travel circle on a map around the post you will be going to, be willing to explore! Look at what day trips are available through the on post travel. Learn some very basic German, the most important being "Ich nich sprechen Duetche, sprechen zie English?", I don't speak German, do you speak English? (I am sure my spelling is horrible, hehe! Teach your kids. Most Germans will know English but will not talk to you unless you make the attempt to speak German first. Be willing to make mistakes and let your kids see it! It will be a valuable lesson on so many levels.
The worst thing you could do is stay on post, stay around only Americans. If you can, live off post. It might be isolating at first but believe me, it is well worth it!
Wow, I am excited for you, enjoy your journey! =)