I personally haven't (not a huge cherry beer fan) but it is definitely possible. A lot of people add fruit to their beer at all different times during the process (boiling, fermentation and bottling).
There is a ton of info out there about adding fruit to beer. I have Sam Calagione's brewing book and he talks about fruit in it. I found it helpful.
How do you get the cherry flavor from the kit you are using? Extract? The reason I ask is you don't want to put too much fruit in and make it over powering...unless that is what you want
Primary: S'mores Stout
Kegged: Centennial Blonde, Dry Stout and Orange American Wheat