a number of Anime like Magical Girl Lyrical Nanoha, Pella Magi Madoka Magica, Fate/Stay Night and Games like Ar Tonelico, Sono Hanabira and Megaman Zero have some soundtracks which are actually Audio Drama's1.
These are more often than not in Japanese. i am wondering if there is a single database/store for their translated scripts, primarily in English.
1: eg. Nanoha has Sound Stage X, Ar Tonelico has Sekai no Owari de Utai Tsuzukeru Shoujo (that's what the Meta Data for "Album Title" is on my iPhone). one of the Megaman Zero ones was of Ceil's Memories before she fled Neo Arcadia and one was of the Weil Numbers acting as Judges i think and one of the Puella Magi Madoka Magica ones served as the basis for the manga Another Story