At our church, the little ones are escorted out of the main worship service early on and do not return until after the readings from the Old Testament, the Psalms, the Epistles, the Gospel lesson, the sermon, the Nicene Creed, the Prayers of the People, and the Confession of Sins. They return during "the Announcements" in time to take part in the Eucharist.
Possible benefits of such an arrangement might be the teaching of the Word in an age appropriate manner, the provision of a break from parenting so that adults might concentrate on hearing the Word, and of course the removal of squirming, fidgeting, distracting little people.
I was raised in a time before "Children's Church". Looking back on those times, I am thankful that this innovation was not a part of my upbringing. I learned our denomination's traditional hymns, the Creeds, the Lord's Prayer, the old Confession of Sins, and even though I could not follow most of what the Apostle Paul wrote, I believe enough things did work their way into my consciousness that I had a pretty solid foundation when it came time for my Confirmation. Another benefit was that I was taught how to sit still and how to appear to be paying attention even when I wasn't. I learned the language of the KJV of the Bible, and most of us would agree that exposing children to foreign languages at an early age is beneficial to their neurological development. In addition, I learned respect for others, and that corporate worship requires a child to give up the attention he/she typically demands.
The benefits of public worship beside one's parents cannot be underestimated, and I encourage people to consider keeping your children next to you and not to send them off to Children's Church.
Over at the Heildelblog this week, there was an interesting discussion on "The Mystery of Children's Church" which those of you with guts might want to join (I warn you that the discussion is not supportive of the mystery).
One comment enclosed the following video which may help those of you who support Children's Church understand where those of us who don't are coming from.