Box Office Mojo has the Friday estimates up:
The DaVinci Code- $29.5 million first day
If that holds, it puts them at #12 all time, right ahead of #13 Star Wars Phantom Menace ($28.5 mmillion) and #14 Passion of the Christ ($25.5 million). Another half million puts them in #11 bumping Harry Potter Chamber of Secrets.
This would bode well for a $70+ million opening weekend which is pretty good for a fairly long "serious" movie.
I expect this turkey to falter after a strong opening. THE DA VINCI CODE has a cult following, not all that dissimilar from Michael Moore's following, and probably quite a bit larger. It's composed of people who want to believe the fictional story is true, even though it's utter nonsense.
Emotion and ideology will drive the cultists to the theaters for the first week or two, but the bottom line is this film has an abysmal 18% rating at Rotten Tomatoes. It's hard to imagine a film that horribly awful (POSEIDON has a 28% rating) having the legs to carry it into the all time box office upper tier.
It'll be a hit, but I'll be surprised if it reaches the heights projected based on its opening weekend.