<a href="http://www.amazon.com/Name-Star-Shades-London/dp/0399256601/ref=sr_1_1?ie=UTF8&qid=1326475441&sr=8-1">The Name of the Star</a> by Maureen Johnson.
It's a young adult novel that my 11 year old daughter was given for Christmas. She said it was "Not too bad" (this from the girl who is obsessed with the Warrior Cats series). I have never been a huge fan of "Rippermania" but I figured if I read it I could have a kind of literary conversation with my daughter. It turned out to not be that bad at all. It's a little too light for my tastes (it is young adult after all) and it took me only a day to read it.
Here's the description: "The day Louisiana teenager Rory Deveaux arrives in London marks a memorable occasion. For Rory, it's the start of a new life at a London boarding school. But for many, this will be remembered as the day a series of brutal murders broke out across the city, gruesome crimes mimicking the horrific Jack the Ripper in the autumn of 1888. Soon "Rippermania" takes hold of modern-day London, and the police are left with few leads and no witnesses. Except one. Rory spotted the man police now believe to be the prime suspect. But she is the only one who saw him. Even her roommate, who was with her at the time, didn't notice the mysterious man. So why can only Rory see him? And more urgently, why has Rory become his next target? In this edge-of-your-seat thriller, full of suspense, humor, and romance, Rory will learn the truth about the secret ghost police of London and discover her own shocking abilities."
I was quite surprised with the ending and I'm actually curious to see how this series goes. I haven't heard of it actually becoming a series but the title "Shades of London" leads me to believe so.