After that, you just monitor the website as much as you'd like for postings that interest you! I tried to keep an open mind, and was at one point talking to families in Hungary and Turkey about spending my summers there.
It's important to be aware that there ARE scammers out there. You should never have to pay the family, or give them any credit information. And be wary of sending out your passport number. Identity theft is a prime motive for scammers, and your passport number is a quick way to do that.
I was also skeptical of anyone unwilling to Skype with me. Video chatting with a stranger can be awkward, but it is reassuring to put a face to the name and verify they're a real person.
Other ways I verified potential families was by google mapping their houses to make sure they were real locations.
One common scam email I got was from families in the United Kingdom (This was a tip-off because most families seeking an English-speaking au pair come from non-English speaking countries. The advantage of having an au pair from another country is improving their children's fluency in another language), offering me thousands of dollars pay per month as long as I send them my passport number. Pretty easy to spot. General rule: If it sounds too good to be true, it probably is.
Most au pair jobs are for longer amounts of time, so if you want to do a summer portion like I am, give yourself plenty of time to find one. That was definitely the most challenging part of my search since my availability was so limited because of school.
If you are looking to do something like this, feel free to e-mail me or facebook me. It's kind of a unique process, so it can be helpful to talk to someone who's done it before (One of my professors gave me the e-mail of a former student who had worked as an au pair, and I found her advice extremely useful!).