Laura Murphy planned on attending her prom at Villa Maria Academy. She paid the $100 deposit, scheduled a limousine rental and asked her date. She ran into a snag, however, and it has nothing to do with what shoes to wear. Administrators of the private, all-girls Catholic high school school don't like Murphy's choice of companion, and they've told her to find someone else or come alone. Murphy, a senior who is openly lesbian, wants to bring her girlfriend of six months, Lindsey Shelton, and believes school administrators are discriminating against them. "They said, "We want it to be traditional....