Katie Couric Good Morning AmericaNBC’s Today is not taking Katie Couric‘s week-long guest stint on rival Good Morning America in stride. In the span of several hours yesterday NBC launched a promo teasing the return of a “legend” on the Monday Today show and a guest-hosting stint by Couric’s enemy Sarah Palin on Tuesday. (NBC refused to name the “legend” before the Monday show, triggering Internet speculation that has turned up such suggestions as Jane Pauley, Bryant Gumbel and… John Legend) Between the “legend” stunt on Today, Katie Couric’s return to morning television on GMA and Gayle King’s interview with BFF Oprah Winfrey on CBS This Morning, tomorrow morning is shaping up as one of the most competitive morning contests in years. It was Couric who conducted that now infamous 2008 interview (on Couric’s former CBS Evening News home) which hurt the then GOP Vice Presidential candidate’s political credibility.