GLEE DOES BRITNEY: Glee, whose second season premieres Sept. 21, will pay tribute to Britney Spears in its Sept. 28 episode, with six of her songs. The announcement was made by creator Ryan Murphy and the show’s cast at this weekend’s Comic-Con in San Diego. Last year, the show dedicted individual episodes to both Madonna and Lady Gaga with story lines devoted to their songs, philosophies and wardrobes. (7/27a)