The New York Times discusses "synecdoche" - mostly the word, but also the film:

Charlie Kaufman has taken a term of grammar that had been suffering in desuetude and put it up in metaphoric lights. The city in New York State whose name he plays upon (possibly derived from the Mohawks' word for "near the pines") is going through industrial hard times, but worried residents can hope to have found their avant-guardian. (Source)

Via Laurel, Roger Ebert lists his Best Films of '08, in alphabetical order. On Synecdoche, New York:

"Synecdoche, New York" The year's most endlessly debated film. Screenwriter Charles Kaufman ("Adaptation," "Being John Malkovich"), in his directing debut, stars Philip Seymour Hoffman as a theater director mired in a long-running rehearsal that may be life itself. Much controversy about the identities and even genders of some of the characters, in a film that should never be seen unless you've already seen it at least once. (Source)