W.C.
Co-op preschools are classes run by (usually) the local Community College that parents enroll in. Depending on your child's age he/she goes to class attended by the parent and the parent has class once a month to attend a parenting class.
When my child was 12 months she went 1 day a week and I went with her. When she was 2 yrs, she went twice a week and I went with her once a week. Both my son and daughter went. There was also a pre-k class for kids that were too young for Kindergarten, they went 4 times a week and I went once a week.
I am an ex-k-1 teacher and I recommend them highly! They are not high pressure learn, learn, learn places. They are loving, experiential places for kids and parents to become who they are meant to be. (That is a very Montessorial phrase-I am a Montessoria trained teacher too.)
They have low numbers of kids, with high numbers of parents to kids so every one has someone to talk and love. There are teachers of kids and teachers of parents.
Even as a teacher of young children, there was lots of things that I did not know about parenting. I think that is an important part of the program that can not be replicated in any other program. I frankly recommend them highly.