Situated in Sin City for charitable endeavors, Selena Gomez was among the performers at Justin Timberlake & Friends Concert a Special Evening Benefiting Shriners Hospitals for Children in Las Vegas on Saturday night (October 23). Joined by her bandmates, the "Wizards of Waverly Place" cutie swapped from a casual top and jeans into a dazzling silver mini dress before taking the stage at the Planet Hollywood Resort and Casino fundraiser. With host Justin Timberlake, as well as Christina Aguilera and T-Pain, among the other acts, the concert coincided with the "Sexy Back" singer's annual S...