A great place to start is with the expat Guide to Munich. We cover how to find work in Germany, learning German, and childcare in Germany (the Berlin guide has recently been updated and includes some pertinent info about Germany).

Hopefully these will give you a feel for what is necessary. I would also recommend checking out expat blogs in Germany as they are a great resource.

Personally, I know many expats are successful in finding work with children in Germany. Your profession as a psychologist should be quite attractive for employers. I would also encourage you to enroll in language school immediately as that will greatly increase your chances. Anyone else have tips or advice? Best of luck!