If you have read the book, don't see this movie. You will be disappointed by the horrible rewrite of the plot and dialog. IMHO they wasted their chance to make a good film.
If you haven't read the book, don't see this movie. Go read the book.

So this is not that charming Italian film about a postman, a woman, and Pablo Neruda. Instead, it's a 3 hour (to be fair, it feels like 5) post-apocalyptic western about postal workers fighting a self-appointed tyrant. You gotta give director/star Kevin Costner (aka one of the most boring leading men ever) some credit for his cojones. Only 2 years earlier, his post-apocalyptic adventure film about a messianic figure, "Waterworld," was a widely and wildly derided. So, he basically makes the same film, but this time without as much water. Also, he directs for the first time since "Dances with Wolves," which, let's remember, he won an Oscar for. Over Martin Scorsese. So maybe you can forgive his arrogance. "The Postman" is insufferably dull and 3 hours too long. Costner is horrible in the lead and I just felt bad for the other actors: Olivia Williams, Will Patton, Tom Petty (yup), Giovanni Ribisi. If you have a weakness for box office bombs, it doesn't get much explosive than this.

It was O.K for a home TV movie. I was entertained and interesting. But it was NOT worth the long library wait or the price to rent from a Red Box. I fast forwarded a lot but not all the way.