There is a great Uniting Church in Redfern (I think its called St Saviours, its Anglican). I attended a few of their serives when I was living there and it was very casual and upbeat with a playarea for children at the back, etc. My friend's father used to be the minister there, but he has since moved on, so I'm not sure what its like now, but I know that lots of young families attend and I found it quite fun.