Folks, I'm literally dancing with joy because I've got the biggest "Dancing with the Stars" scoop since HEATHER MILLS' wooden leg went wonky during the show - TV icon FLORENCE HENDERSON, known to millions as Marcia Brady's mom, will twirl the light fantastic on the show next season...at the spry young age of 74! And be warned, all you contestants, Florence ain't in it for the fun. She's telling pals: "I'm determined to be the oldest woman to win this competition." (YOU GO, GIRL...er, Ma'am.)