Yes, there won't be a single release.
That is what Sony said in an email they sent to Damien, even though their press announcement said that "This Is It would be a brand new SINGLE. They even said that the song wouldn't be downloadable individually from itunes. Strange huh?
I visit several music forums and nobody can understand why Sony would waste this opportunity to release a single that would get so much interest. It's craziness. The best guess is they are trying to force people to buy the new 'This Is It' album, but that's ridiculous. The song will be unveiled on 12th October but the album won't be out for another two weeks after. They should have just released the album with the new song on it, without officially 'unveil' the song. That way people would be more likely to purchase the album to listen to the song. As it is, people will have 2 whole weeks to download the song illegally and not buy the album at all.
I certainly won't buy the album, but I would have bought the single. In fact I already pre-ordered it on HMV, and I'm still waiting for them to remove it from their site.