Cher, Whoopi Goldberg, Joan Rivers, Bette Midler and Naomi Campbell are backing a campaign to help the homeless in New York. The stars have autographed brooms which will be auctioned for homeless charities at June's (08) annual SoHo Stroll. The event, founded by Manhattan philanthropist Henry Buhl, will include a walk through downtown New York, as well as a sale of brooms signed by more than 30 celebrities.