It certainly comes as no surprise, but Apple began informing its customers today that Quattro Wireless will begin the process of closing down its existing ad network so it can focus on iAds. “We believe iAd is the best mobile ad network in the world, and starting next month we’re going to focus all of our resources on the iAd advertising platform,” said Andy Miller, Apple’s vice president of iAd. “We are no longer accepting new campaigns for the Quattro Wireless Network, and we will soon begin winding down existing campaigns. As of September 30, we will support ads exclusively for the iAd Network.”

Miller said Advertisers are seeing a huge spike in the time customers are spending interacting with ads. He compared them more to TV ads than traditional online ads.

Apple purchased the Quattro Wireless ad network and used it as the basis for its iAd network, which the company unveiled in early April.