SAY IT AIN'T SO, REGIS!: Uh-oh. Looks like ABC's quizzer Who Wants to Be a Millionaire is cribbing notes from NBC's Weakest Link � by trolling the B-list for publicity-hungry "celebrity" contestants. Three upcoming shows (airing Feb. 11-13 at 10 pm/ET) will find Regis interrogating alums from TV producer Aaron Spelling's stable. These include: Hotel's Shari Belafonte, Melrose Place's Thomas Calabro, Love Boat "Doc" Bernie Kopell, Cheryl Ladd of Charlie's Angels and T.J. Hooker's William Shatner. (Hey, didn't he already do Weakest Link's all Star Trek episode?)