I must admit, I am not the biggest fan of bethesda
My son went to bright beginnings in Middletown (next to cedar lane elem. school), very nice and family organized preschool.
My daughter went to 'children at work' - our all time favorit - but not run by a church.
they are on 301, offer preschool, kindergarten and daycare, have a great backyard, a butterlfly house, some reptiles (in cages

), fish, huge sandboxes and do a lot of hands-on stuff and fieldtrips each week AND are very inexpensive.
I've also heard good things of green acres on rt 13 and tried several times to get into st. andrews preschool, but we have never made it in.