Georgina Chapman is bringing her red carpet looks to teenagers with a prom dress collection for J.C. Penney.Pearl, which hits stores on March 1 and is already available online, will feature formal gowns, party dresses and some casualwear, all below $250.The 36-year-old designer, whose Marchesa creations are popular among celebrities including Diane Kruger, Blake Lively and Kristen Stewart, told WW