As thousands cheered, private citizen William Jefferson Clinton, 54, moved to Harlem on Monday, officially beginning his post-presidency to an adoring crowd that gave him a hero's welcome. On Tuesday, he was already in business, holding a press conference with Grammy-winning record producer and singer Kenneth "Babyface" Edmonds, 43. The two are teaming up to fight AIDS in Africa through a new fund-raising and educational initiative. Peter Paris, a spokesman for the International AIDS Trust, told the Associated Press that Edmonds would go on a fact-finding tour through African communities ravaged by AIDS, and would raise money to fight the disease by staging concerts and producing a CD. (Among those for whom Edmonds has written songs: Mariah Carey, Celine Dion, Madonna and Michael Jackson.) As for Monday's festivities centering around Clinton's arrival, "I want you to know that I want to be a good neighbor in Harlem," the former chief executive said during a rally before he occupied his new office in New York's uptown, primarily African-American community. Acknowledging that his presence could be threatening, Clinton said, "I'm glad property values are going up, but I don't want small-business people to be run out because I'm coming in." In other Clinton news, his hometown of Hot Springs, Ark., has decided to put the ex-Prez on a baseball card, with a photo of him playing golf on one side and facts about his life in Hot Springs on the other. That Bill, what a card.