Visible crew/equipment: When Phoebe tells Piper that she's on a deadline and hangs up the phone, in the next shot as Piper says that she's going to Phoebe at the newspaper, the shadow of the boom pole/mic is visible on the wall behind Piper, at the top of the screen. (00:26:45)
Visible crew/equipment: Just after Paige orbs into Phoebe and Cole's hotel room, a boom mic can be seen at the top of the screen.
Chosen answer: Her agent/manager negotiated a special billing as part of her contract. It distinguishes her from the rest of the cast, probably when she became a producer on the show.
JC Fernandez