Oooh, good thread!
I've tried
the Baby ESP trial and that was really good, would be fantastic for a new mum in the first few weeks!
I haven't downloaded one yet, but I'm going to get one of the baby monitor ones - basically when you put the baby down, you leave the phone near them, and when they make noise to a certain level, it will call another designated phone!! Thinking this will be very handy for Xmas travel!