We've got your all-access pass to everything Britney Spears!The singer just started her 2-year residency at Planet Hollywood in Las Vegas -- and toofab was backstage and in the VIP section of the show to bring you all the goodies you won't see anywhere else.Click here to see our review of the full concert and see more video. Keep reading to get the dirt from inside the Axis Theater.1.) Britney Gets By with a Little Help from Her "Friends."Before hitting the stage for her big opening night, Spears relaxed by watching some DVDs in her dressing room. Her show of choice, at least on Friday night, was "Friends." Yep, even Britney can't resist the awesomeness of Ross, Rachel, Monica, Chandler, Phoebe and Joey. They'll be there for you!2.) Spears Is In the Vegas Inner Circle Now!A Sin City legend officially welcomed the pop star to Las Vegas,...