Hi, we got our current au pair from aupair world and she is LOVELY!
I agree with everything StillSquiffy said but would add one other thing. If you can do it, get your best one or two candidates over here for a weekend for a trial run. It is well worth it.
I say that because when we shortlisted all the candidates after phone and skype interviews it boiled down to two and they were both great by the sounds of it, chatty, good English, caring, engaging, answered questions about safety very well. And then we flew them over (on different weekends) and I couldn't believe the difference with one of them.
From Friday when she got here to Sunday lunchtime she didn't say anything, nothing, other than to reply with a yes or no to my questions, she did not attempt to play with my daughter, oh and she only got up at 11 am on Saturday and that was because I asked her to get up. No idea why she bothered coming over at all.
I first thought what a waste of money on her flights but it was actually money very well spent. I would have happily chosen her based on phone and skype interviews and could have ended up with a miserable thing in my house and with my child.
Then we flew our current au pair over and the moment she turned up we knew she was the perfect one for us. She was lovely from the word go.
Sorry to go on, I am just trying to say that if at all possible, interview in person.