This is a case where I would "let my conscience be my guide". I, personally, would not feel comfortable getting hired if I knew I was pregnant and did not tell my employer.
Also, are you sure you want to get a job? You are moving soon, you are pregnant, you have a child already, your husband will be starting a new job, and school will start in August. It is already almost the end of June. I imagine you need to look for a house, get established with a doctor for prenatal care, find daycare for your child (if you are going back to work), and deal with tons of other things that come with moving. It all sounds extremely stressful even if you don't have a job! If I was in this situation and we could survive on Dh's salary, I wouldn't even consider getting a job right away!! I would probably wait and see if anything came up for the second semester of the school year. Teachers leave at all different times, so maybe you could start a job in January or beyond.
I hope everything works out for you.