Alli Sims ASIMS102707_01.jpgOur videographers just caught Britney Spears' loyal assistant Alli Sims heading out in search of fishnets - for her Halloween costume, of course! Sadly, she wasn't willing to get into specifics as to what her costume might be. Still - if she's shopping for fishnets, we're guessing her costume tonight's going to be even hotter than the Tony Romo get-up she broke out over the weekend!