GOOD MORNING: On the floor of the Democratic Convention at the Boston’s Fleet Center Monday, Alex and Alex were fighting to interview Ron Reagan. They were Alexandra Kerry and “Alexandra Tanner” (actress Cynthia Nixon). The former Alex was trying to query Reagan for a docu she is shooting on her father and Nixon was sparring with questions for her role in Robert Altman’s “Tanner on Tanner.” At day’s end Altman admitted to me the scene was “riveting” as the two women fought to get quotes from Reagan for their respective films. Michael Murphy, who stars as Tanner admitted to me the scene was one for the books. He had already interviewed Clinton’s chief of staff, John Podesta, and Madelyn Albright on camera about her (definitely negative) opinion of the Iraq war. And Altman caught Hillary Clinton for a brief scene. Altman, fighting through laryngitis, is juggling four digital cameras on the convention floor and has to wind shooting in time for the edit of the first of three segs to air Aug.15. Monday night, Murphy was back on camera at “Rock the Vote” at Rowe’s Wharf in Boston Harbor. Today he returns to the convention floor where he’ll interview Tom Brokaw, DeeDee Myers and Howard Dean, among others. Robert Redford had already filmed a major seg in N.Y. before the troupe hied to Boston.THERE’LL BE MORE movie cameras on the convention floor this week — one from HBO stars rapper Andre 3000 and is a docu about the Atlanta-born member of OutKast. This project is not to be confused with a period musical project for Andre 3000 under discussion at HBO. The one filming segments on the Demo (and later at the Republican) convention is a project from “Declare Yourself,” with Norman Lear exec producing, Donovan Leitch producing, Marc Levin directing. Lear calls Andre (surname Benjamin) “a terrific lad.” And reminds me he was the m.c. at the “Declare Yourself” event March 2 at the (original main) Beverly Hills Post Office where Andre registered to vote for the first time. He’s 29. “I have never voted — that’s why I’m here,” he told the crowd. Lear says the campaign has resulted in 260,000 newly registered voters. The movie about Andre, Lear says, “will show the real world of democracy.” “I want to be involved in this campaign,” Andre told me and left no doubt he wanted to be involved supporting John Kerry. Leonardo Di Caprio was also among those at the “Declare Yourself” event when he said he, too, wanted “to be involved in this campaign.” … No one in the showbiz community has been more involved so far at the convention than Ben Affleck who has made (speaking) appearances so far to delegate meetings from Massachusetts, R.I., North Carolina and Florida, and met with Hillary Clinton. He also took time out to see his beloved Bosox play. His zeal is, to date, unmatched by fellow thesps — but the list is growing. Among those already there and/or arriving: Glenn Close, who spoke Monday, John Cusack, Carole King, Richard Dreyfuss, Alec Baldwin, Emmylou Harris, Mark Canton, Alan and Marilyn Bergman, Larry and Laurie David. When the convention winds, a bus-and-trainload of celebs takes off cross-country to pitch for the Kerry-Edwards ticket. It is reminiscent of the days when Lauren Bacall-Humphrey Bogart-Henry Fonda ditto’d for the Demos. THIS, TOO, IS SHOWBIZ: Jerry Goldsmith was buried Friday at Hillside Memorial Park and Hollywood Bowl Orchestra conductor John Mauceri tells me this story about the incomparable Jerry. When the country closed down Sept. 11,, the Hollywood Bowl was, of course, among those whose programs were KO’d. It was set to reopen on the 14th and Mauceri asked several top tunesmiths if they would write something special to commemorate the sad day. “Jerry called back and said I may have something” and on the evening of the 13th, told Mauceri he did indeed have a piece. JoAnn Kane, principal copyist in the biz, worked all night to copy the piece for orchestration., It was on the stands of the Bowl orch on that morning of the 14th. They rehearsed and performed it that night. On July 9, when the Bowl’s concert paid tribute to the composers of movie and TV music, Mauceri included pieces of themes Goldsmith wrote for “The Waltons,” “Dr. Kildare,” “The Man From U.N.C.L.E.,” “Room 222,” and “Star Trek.” Mauceri knew Goldsmith was desperately ill at home. He phoned him from the Bowl stage to tell him the orchestra was about to play his creations — he left the phone open for him to hear the night before his 75th birthday. … A limited edition CD of songs by another music great, Jimmy McHugh, celebrates his 110th birthday. The disc contains “I’m In the Mood for Love” by Rod Stewart, also by Barbara Streisand, “On The Sunny Side of the Street” by Cyndi Lauper, and John Pizzarelli, “Let’s Get Lost” by Diana Krall and Terence Blanchard. A bio on McHugh is being written by London Times jazz critic Alyn Shipton. … Lance Armstrong was not only joined by Sheryl Crow in Paris — Jake Scott is there to film another Nike commercial with him … Producer-director-writer Steven Sawalich and producing partner Brett Donovan have set up offices on the Lot in Hollywood to cast their feature “The Music Within” which they describe as “Forrest Gump” meets “A Beautiful Mind.” … Publicist Julian Myers and his wife Patsy have trademarked “Amigo Day” and are establishing it for anyone anywhere to celebrate with anyone in any way — the first Sunday of any month. Want more? (310) 827-9089.