Sherlock Holmes sure is making a comeback these days. In addition to the different TV shows and movies that are out right now, there are also a few good teen books that you might want to try:
Secret Letters by Leah Scheier: Dora travels to London to meet Sherlock Holmes, who might be her biological father, and ask for his help in a blackmail case. Along the way she gets some help from a handsome young detective.
Death Cloud by Andrew Lane: This is the first in the Young Sherlock Holmes series and tells the story of a fourteen-year-old Sherlock on his first murder investigation. If you like this one there are three more in the series.
Eye of the Crow by Shane Peacock: This is the first book in the Boy Sherlock Holmes series (not to be confused with the Young Sherlock Holmes series mentioned above). In this one, thirteen-year-old Sherlock ends up a murder suspect and must solve the crime to clear his name.
No Place Like Holmes by Jason Lethcoe: An aspiring detective gets a big break when he goes to England to visit his uncle who lives next door to Sherlock Holmes.
And don't forget, there's always the original stories by Sir Arthur Conan Doyle as well. Have you read any of them?