In the Philadelphia area, the Phila Folksong Society has a program-it's called the Odessey program, where they fund musicians' visits to schools, kids' hospitals, etc.

One thing that may help you get gigs in schools is if you connect the songs you sing with some history lesson, some culture kids are learning about, etc. Kim and Reggie Harris have done a program on songs of the underground railroad. Somebody has done a program on the Vietnam war, and protest songs. I know somebody who does songs of the sea from the era of sailing vessels. I have seen a slide show on labor history, and instead of having a recorded sound track, one or more singers accompanied it, live.

I have also seen musicians who got gigs as sort of "visiting music teachers" in private schools or preschools.

Good luck!

Mary McCaffrey