Apple has announced a partnership with marketing firm The Dentsu Group to expand Apple’s iAd mobile advertising platform to Japan early next year. According to the announcement, Dentsu will handle the selling and creative execution of iAds in Japan, while Apple will host, target and deliver the iAds to its iOS users. In addition, Dentsu subsidiary cyber communications, inc. (cci) will provide one-stop services for iAd in Japan including creative…