Photo booth problem


hey, i got a problem with photo booth app on osx 10.5.8, the app shows on the dock but it has an interrogation mark, i've been lookin on finder for the app but i think my sister deleted it, is there some way to recover it without using the extra disks? because i dont have them =(, or if any one could send me the .app would be pretty awesome =) thank you macosx community