NEW YORK (AP) — Jon Stewart is on the board of the foundation building the Sept. 11 memorial in New York.The comedian-activist was appointed to the National September 11 Memorial & Museum board of directors Thursday afternoon. Stewart thanked the board and its chairman, Mayor Michael Bloomberg, and said he would do what's needed to help.The host of the Emmy-winning "The Daily Show" on Comedy Central recently used his show to champion a federal bill that provided billions to treat workers who became ill from exposure to toxic World Trade Center dust.Foundation president Joe Daniels says Stewart is an important public figure and a regular New Yorker who saw the world change on 9/11.The memorial — twin reflecting pools set above the fallen towers' footprints — is set to open to the public by this Sept. 11.___Comedy Central is owned by Viacom Inc.___Online:http://www.national911memorial.org