The New York Times has a terrific article up about Stephen Sondheim. It mainly has to do with the current trend of restaging his major works in small, mini-orchestrated productions. I don't know that I like this trend but I suppose it depends on the show and the cast and how cleverly it's all staged.
Also, the American Theater Wing — they're the folks who give out the Tony Awards — have posted a one-hour podcast conversation with Mr. Sondheim. You can download it over on this page or listen to it live there.