"Kids America," the last nationally aired childrens' radio program, went off the air Friday, in part because grants making up half the syndicated program's budget would be discontinued, according to the Corp. for Public Broadcasting. The show, produced by WNYC and carried by 26 public-radio stations, folded after nearly four years of live broadcasts. The 1 1/2-hour program, which won a Peabody Award, included a fast-paced mixture of games, music and "Sesame Street"-style teaching. About 6,000 children called the show's toll-free number each week to talk with hosts Kathy O'Connell and Larry Orfaly. Richard H. Madden, director of the CPB's radio program fund, called the show "a marketing failure" because so few of the nation's 300 public-radio stations carried it.