Lots of good stuff in the comments for this post. First up is boloboffin’s great series of posts that covers a lot more aspects of the movie that I did. Here’s an index :

1. The resurrection of Jesus is not historical.
2. Pilate was the instigator of the death of Jesus, not Caiaphas.
3. Pilate was not the sensitive, thoughtful ruler portrayed in the film.
4. It wasn’t blasphemy to identify yourself as the Messiah or the Son of Man.
5. The Jews who spoke with Jesus were trying to intercede on Jesus’ behalf, not railroad him.
Interlude - Crucifixion Porn
6. The cross is wrong.
7. Roman soldiers were present when Jesus was arrested.
8. Koine Greek, the most common language of the day, isn’t used in the film.
9. Mary the mother of Jesus had other sons.
10. Nails in the wrist, not in the hands.

Also in the comments, Rowdy pointed out this Reuters article that I missed. The history geek quotes alone make this an articlke that you should check out :

Mel Gibson’s portrayal of the final 12 hours of Jesus in his film “The Passion of the Christ” has been hailed as the gospel truth by some believers, but many scholars complain that it is riddled with historical errors.

Their complaints range from inaccuracies about hairstyles and clothes to a lack of gospel context in the film which has raised a furor among Jewish groups who fear its graphic depiction of the crucifixion will fan anti-Jewish violence.
. . .
Experts say this was his first mistake as Greek was the language spoken in Jerusalem during Jesus’s time, along with Aramaic and some Hebrew spoken by Jews.

“Jesus talking to (Pontius) Pilate and Pilate to Jesus in Latin!” exclaimed John Dominic Crossan, a professor of religious studies at the Chicago-based Roman Catholic De Paul University. “I mean in your dreams. It would have been Greek.”

Latin was reserved for official decrees or used by the elite. Most Roman centurions in the Holy Land spoke Greek rather than Latin, historians and archaeologists told Reuters.

The mistakes, experts say, didn’t stop with the wrong language, which Crossan — who speaks Latin — said was so badly pronounced in the film that it was almost incomprehensible.

“He has a long-haired Jesus…Jesus didn’t have long hair,” said physical anthropologist Joe Zias, who has studied hundreds of skeletons found in archaeological digs in Jerusalem. “Jewish men back in antiquity did not have long hair.”
. . .
Crucifixion was a common punishment meted out by the Romans to rebellious Jews during Jesus’s time. The Romans crucified so many Jews, said Zias, that “eventually they ran out of crosses and they ran out of space.”

The depiction of the crucifixion was the part of the film most riddled with errors for Zias, who studied the skeleton of a crucified Jewish man from Jesus’s time — the only remains ever found of a crucified victim from antiquity.

Zias said Jesus would not have carried the entire cross to the crucifixion as vertical beams were kept permanently in place by the ever efficient Romans.

“Nobody was physically able to carry the thing (the entire cross).It weighed about 350 pounds,” Zias said. “He (Jesus) carried the cross-beam, maximum.”

And finally, on the subject of the reported anti-semitism of the film, Ezra and Jesse over and Pandagon have said most of what I wanted to say on the subject, but I’d like to add that in one sense, Gibson does seem to be correctly quoting the Bible :

Matthew 27:22-25

“What shall I do, then, with Jesus who is called Christ?” Pilate asked.

They all answered, “Crucify him!”

“Why? What crime has he committed?” asked Pilate.

But they shouted all the louder, “Crucify him!”

When Pilate saw that he was getting nowhere, but that instead an uproar was starting, he took water and washed his hands in front of the crowd. “I am innocent of this man’s blood,” he said. “It is your responsibility!”

All the people answered, “Let his blood be on us and on our children!”

Leaving aside the Bible’s sketchy accounts of history, this is just one of four accounts of the crucifixion. Why did Gibson reportedly choose this one? Well, as the title suggests, “The Passion of the Christ” is made in the passion play tradition. Here’s what the Anti-Defemation League has to say about that :

The central narrative of Christian theology is the passion, i.e. the trials and crucifixion, and resurrection of Jesus. There are four different accounts of the passion in the gospels of Christian Scriptures, in which Jews play different roles. All these accounts culminate in the death and resurrection of Jesus as revealing God’s saving power available to humanity. Good Friday and Easter celebrate respectively the crucifixion and resurrection of Jesus as the high points of Christian creed and experience. Christians frequently present dramatic representations of this narrative known as “passion plays.”

Because much of Christian Scriptures were written in polemical style that often portrayed Jews and Jesus–and therefore Judaism and Christianity–as adversaries, a common interpretation of the crucifixion was that the Jewish people were responsible for killing Jesus. According to this interpretation, both the Jews at the time of Jesus and the Jewish people for all time bear a divine curse for the sin of deicide. Throughout nearly 1900 years of Christian-Jewish history, the charge of deicide has led to hatred and violence against Jews of Europe and America, and various forms of anti-Semitic expression. Historically, Holy Week (the week leading up to Easter Sunday) was a period when Jews were most vulnerable and when Christians perpetrated some of the worst violence against their Jewish neighbors.

In 1965 at the Second Vatican Council in Rome, the Roman Catholic Church took formal steps to correct this interpretation of the passion. In its document, Nostra Aetate, the Church officially repudiated both the deicide charge and all forms of anti-Semitism. Most Protestant churches followed suit, and since 1965 many Christians have worked cooperatively with Jews to correct anti-Semitic interpretations of within Christian theology. Understanding the influential role that passion plays have exercised in the spread of anti-Semitism, the Catholic Church today urges great caution in all dramatic presentations of the passion to ensure that they not furnish any impetus for anti-Semitic attitude or behavior.

As you’ve probably heard, Gibson is a member of a Catholic splinter group that’s rejected Vatican 2. Does this make him an anti-semite? I’ll leave that up to others to decide since I haven’t seen the movie, but the evidence does seem to lean in that direction.