Central Presbyterian Church (908) 273-0484 (my 3 daughters attended). They offer a drop in option for children as young as 6 months & a 2 1/2 year old class.
Jewish Community Center (908) 277-3919
The Connection for Women & Families (908) 273-4242 (available for 2 1/2)
The Learning Circle (908) 273-7040 is a day care affiliated with the YMCA here in Summit. Infants from 6 months through kindergarten is available. My daughters also went here.
If you would like more information on Summit (or surrounding towns) please contact me.
There are a few:
Weekday Nursery School (70 Maple St, Summit, NJ 07901)
Nursery School of Christ Church (74 Park Ave, Summit, NJ 07901 - (908) 277-1720)
St. Teresa's Preschool & Kindergarten, 306 Morris Avenue, Summit
All the best,