Apple has announced a subscription service for publishers of content-based applications created for the the iPad, iPod touch and iPhone.

Reader’s who wish to subscribe to a magazine’s application can now do so by clicking one button in the Apple App Store. Publishers set the price and length of subscription (weekly, monthly, bi-monthly, quarterly, bi-yearly, or yearly) and Apple keeps its standard 30% share of each subscription sold. Subscriptions will renew automatically unless the consumer cancels it.

Publishers can also sell subscriptions to their apps outside the Apple App Store, keeping 100% of the profits when a subscriber signs up through an external site. However, Apple requires the same subscription offer, or a better one be made inside the App Store as the one made outside it. Publishers must provide their own subscriber authentication process inside the Apple App Store for customers that have signed up outside the app, according to the announcement from Apple.

In addition, Apple said publishers are no longer allowed to provide links within their Apple apps to outside sources, such as web sites which allow customers to purchase content or subscriptions outside the application.

As for the much desired subscriber contact information: if a user subscribes through the Apple App Store they are prompted with a button which asks if they would like to share their information (name, email and postal code) with the publisher. “Publishers may seek additional information from App Store customers provided those customers are given a clear choice, and are informed that any additional information will be handled under the publisher’s privacy policy rather than Apple’s,” according to the announcement. Subscribers who sign up outside the Apple App Store are bound by the privacy policy of the individual publisher.

2: The Magazines for Couples, has six apps on the iPad with plans for two more in the near future. Its publisher, Diane Hall said today’s announcement gives her team direction on the platform. “The announcement is great for us because it is clarifying,” she said. It gives us another tool in the business plan to build loyalty on our apps.”

Hall said she appreciates the difficulties Apple’s restrictions might cause for more traditional print publishers, but thinks you have to play by the rules of the platform. “When you go onto a new platform you have to adjust your business plan to fit the conditions there,” she said. “I think users will opt to subscribe to applications because it is easy.”