Apple on Thursday announced that not only would Warner Bros. titles be available for purchase on the iTunes store the same day and date as DVD release, but so too would movies from 20th Century Fox, Walt Disney Studios , Paramount Pictures , Universal Studios Home Entertainment, Sony Pictures Entertainment , Lionsgate, Image Entertainment and First Look Studios. (press release)

Even before the full extent of the deal was revealed, analysts were talking about the consequences for the DVD business. “Time Warner To Help Kill Off DVD Rentals” was the headline of Michael Learmonth’s piece in Silicon Alley Insider Thursday morning.

What does all this mean? It means Time Warner is finally ready to start weaning itself from DVD sales, which have been Hollywood’s biggest revenue source for years.

It also means that if Blockbuster — or Netflix, for that matter — doesn’t figure out electronic delivery, it is toast. And it means that Sony and Toshiba just incinerated a pile of money in a useless DVD format war. (link)

What convinced the Hollywood studios to cut this deal with Apple’s (AAPL) Steve Jobs? According to Time Warner’s (TWX) Bewkes, the company had been experimenting with “day and date” video on demand (VOD) release for several months and found that DVD rentals only fell by 3 to 5 percent and sales of DVDs actually increased. Since VOD is so much cheaper than printing and distributing discs, it looked like a no-brainer.

“Taking a customer and moving that person over from rental-physical over moving them to VOD day-and-date is like a 60 to 70 percent margin instead of a 20 to 30,” Mr. Bewkes said, according to the New York Times. “So it’s about a three-to-one trade.” (link)

Among the titles immediately available for download on iTunes: “Juno,” “Cloverfield,” “I Am Legend,” “There Will Be Blood,” “American Gangster,” “The Diving Bell and the Butterfly,” “Alvin and the Chipmunks” and “Walk Hard: The Dewey Cox Story.”