MTV spoke to Toby Jones, who voiced Dobby, the house elf in Harry Potter and the Chamber of Secrets. He says that Dobby will not appear in Harry Potter and the Order of the Phoenix:

When Harry Potter tricked Lucius Malfoy into freeing his house elf, Dobby, at the end of "Chamber of Secrets," he might have inadvertently magicked the helpful servant right out of the series. Dobby hasn't appeared in any Potter films since and won't be appearing in the upcoming Harry Potter and the Order of the Phoenix either, according to Toby Jones, the actor who voiced him in the series' second installment.

"I know that the filmmakers have a problem with each new film because the books are getting longer - there's so much to include in them," Jones remarked.

While Dobby's absence will not shock fans who have been following the films closely, it does open up some plot questions. In the book, it is Dobby who both divulges to Harry the secret of the Room of Requirement (where Harry and the other members of "Dumbledore's Army" meet to practice forbidden defensive spells), and materializes to warn Harry that his secret hideout is no longer safe from the prowling eyes of the increasingly powerful Ministry of Magic informant (and new Defense Against the Dark Arts teacher), Dolores Umbridge. With Dobby's absence, it is unclear how these matters will be handled in the film.

As one house elf leaves, another one enters. Kreacher, servant to Sirius Black's estranged family, will make his first film appearance in Harry Potter and the Order of the Phoenix.

Harry Potter and the Order of the Phoenix opens worldwide in July 2007.