Joseph Kennedy III has launched his campaign for the congressional seat now held by retiring U.S. Rep. Barney Frank. Kennedy released a video announcement on his campaign website Thursday morning before heading out on a campaign swing through the district. Kennedy, the son of former U.S. Rep. Joseph Kennedy II and a grandson of the late Robert F. Kennedy, recently moved from Cambridge to Brookline, part of the state’s newly redrawn 4th Congressional District. The family has deep ties to the Boston suburb. Brookline is the site of the birthplace of Kennedy’s great-uncle, the late President John F. Kennedy. … Amanda Knox has a book deal. The young exchange student whose conviction in Italy and eventual acquittal on murder charges made headlines worldwide has an agreement with HarperCollins to tell her story. The 24-year-old Seattle resident, imprisoned for four years in Perugia, Italy, has not publicly discussed her ordeal beyond a brief expression of gratitude upon her release last October. “Aided by journals she kept during her imprisonment, Knox will talk about her harrowing experience at the hands of the Italian police and later prison guards and inmates,” HarperCollins said in a statement Thursday. The book, currently untitled, is tentatively scheduled for early 2013. … Aretha Franklin and Stevie Wonder will sing at the private funeral Saturday of Whitney Houston in what promises to be a very musical service. Publicist Kristen Foster also confirms that invitations went out to Houston’s ex-husband, Bobby Brown; her co-star in “The Bodyguard,” Kevin Costner; and Oprah Winfrey. Houston’s longtime musical mentor, Clive Davis, will speak at the funeral. The eulogy will be given by gospel singer and longtime family friend Marvin Winans.