Yes, same here.
It's not a RULE you have to follow. We sat down a lot as kids. My mother gave us these guidelines:
You stand whenever the priest comes out of the altar
You stand during the Gospel reading
You stand during the Our Father and Creed
You DEFINITELY stand during the epiclesis (the prayer during the consecration of the Gifts)
And she said that from the epiclesis on, you stand because you are in the prescence of the Eucharist
And you don't sit down after you receive Communion because other people are still receiving.
So, while we were allowed to sit, we still HAD to stand at certain points if nothing else, and there are good reasons for that standing. But giving little legs a rest is very much ok!
I'm sorry that it was in mostly Greek. That does make it hard, and nearly nullifies the teaching aspect of the services for your children. It's really hard for them to grow up with an Orthodox understanding of theology if they never hear anything in English.
There's a really sweet little book you can get from Concilliar Press that describes what is happening in the Liturgy and has some children's prayer. We had it as kids and I think it's a great gift to give to anyone at a birth, baptism, etc.http://conciliarpress.bizhosting.com/guardian_angel_children_s_prayer_book.html