MAY AND DECEMBER ARE OUR FAVORITE MONTHS: Harrison Ford takes up with Calista Flockhart, and they could be married by the time you read this. . . . Paula Abdul does everything but publicly proposition eventual American Idol runner-up Justin Guarini every time he sings. . . . At least one person in the know discounts stories of hot and heavy doings between Kim Basinger and Eminem during the filming of 8 Mile, in which she played his mother. Other observers think, why not? Compared with her ex-husband, Alec Baldwin, the rapper sounds like Mr. Warm and Cuddly.