If you’re lucky, you can get the press to do some marketing for you. And if you’re really lucky, you can get Apple (AAPL) to do your marketing for you.

The newest set of Apple ads focuses on apps made by big brands–Barnes & Noble, Pizza Hut, Gap, Epicurious and Zagat–that can certainly afford their own promotional pushes.

And certainly those guys paid cash or some other kind of compensation for the consideration, right? Not as far as Advertising Age can discern: The trade mag notes with a bit of dismay that there isn’t any kind of application process to get into Apple commercials and that “the marketers in question didn’t request to be in the commercial at all.”

As far as I can tell, this mirrors Apple’s overall policy for iTunes, whether you’re talking about music, movies or apps: Unlike traditional retailers or even competitors like Amazon (AMZN), there’s no way to buy shelf space at Apple’s digital store. If you want Apple to shine a spotlight on your stuff, you just have to hope that someone there likes your stuff. AdAge:

Apple did not immediately respond to requests for comment on the story, but it’s clear the company looks for apps that use as many aspects of the iPhone as possible, such as sound, shaking, GPS or the camera. It also seemed to favor anything that highlights features of the newest operating system, such as in-app payment. Additionally, it appears that brands are given more credit for good user experience than whether or not they can match Apple’s own cool factor.

Pizza Hut, for instance, doesn’t have many common associations with the tech giant but its app was the first from the quick-service industry that let users place delivery orders.

*Note that Apple’s app ecosystem has grown faster than its ad agency expected; the new campaigns announce that there are 75,000 apps, but that number is 10,000 short, according to a release Cupertino put out yesterday.

The deal is an interesting one, and for a number of reasons. Unlike Brooks–or The Eagles or Journey, who have similar pacts with Wal-mart–AC/DC is still under contract to Sony (SNE) BMG’s Columbia Records. By inking such a deal, Columbia almost certainly risks alienating other retailers, who can’t be happy to see AC/DC’s first album of all-new material in eight years become a Wal-Mart exclusive. Among those retailers: Apple’s (AAPL) iTunes Music Store, where AC/DC has so far refused to distribute its music.

The deal also comes at a time when Wal-Mart and other big retailers are reducing their CD shelf space. It’s been estimated that Wal-Mart, Circuit City (CC) and Target (TGT) have cut between 5 percent and 23 percent of their CD inventory in the last two years. Which means that retail exposure, which was once a given for many bands, is becoming increasingly dear. So much so that it’s a negotiating point, and–in Wal-Mart’s case–enough of one for big-name acts to justify allowing the retailer to sell their new releases on an exclusive basis.

“Shelf space has shrunk so much over the last five years that for anyone to give you shelf space and exposure is a big deal,” Terry McBride, chief executive of Nettwerk Music Group, recently told the New York Times. “Should the labels be worried? There’s been a move away from the labels for a number of years now. And it’s not necessarily their fault. The shelf space to have those records sell just isn’t there. That’s the market reality.”