NEW YORK (AdAge.com) -- Men's Health magazine has introduced an iPhone application that uses new software capabilities to sell additional content directly through the app itself.

The approach, which Apple says appears to be a first for magazines and even media companies, could open up a new digital distribution channel -- one that, crucially, comes with circulation revenue. That's a potentially valuable piece of the puzzle for media companies, which have found that online ad revenue still pales in comparison to print-ad revenue.

The $1.99 app, the first from Men's Health, comes with photos, instructions and the ability to track one's progress for 18 workouts and more than 125 exercises. But the app also offers additional groups of workouts for 99 cents and up. Apple takes 30% of sales revenue for the original download as well as any expansion sales that follow.

The in-app purchase option only became possible Tuesday, when Apple released a new operating system for the iPhone and iPod Touch.

"A lot of previous apps were one-and-done purchases, where you buy Tetris for $1.99, play it for a while, then forget about it," said David Zinczenko, editor in chief of Men's Health and editorial director of Women's Health, which are published by Rodale. "We have the opportunity to upsell anyone who has purchased the base app. It could be workouts, [magazine features such as] 'Eat This Not That,' it could move into the fashion and grooming field. It could be anything; that's what's really exciting for us."

Rodale plans to introduce a similar Women's Health app soon. It's also developing apps that, unlike these, integrate advertising.

The company uses outside programmers to build the apps but uses magazine staff as much as possible for creative, editorial and design decisions. "If you go to a developer and say, 'I want a turn-key app that I can put on the iTunes website,' they're going to quote you something like $80,000 or $100,000 and not do it in a way that accurately reflects your brand," said Matt Bean, articles editor at Men's Health, who handled heavy lifting on the new app. "We are equipped to move fast and light in this new space. We don't have to sit there waiting for some developer to clear space in their schedule."

Magazines have already been busily trying to make the most of the iPhone and iPod Touch. Conde Nast's Lucky at Your Service app helps users find certain bags or shoes in stock at nearby stores. Some publishers and developers are considering ways to sell versions of actual issues, tailored for iPhone consumption, through the App Store or iTunes.

If other media companies haven't started trying in-app purchasing yet, it won't be long. For now other apps using the function include games such as Ngmoco's "Star Defense," which sells new galaxies to play for $2.99, and Pangea's "Enigmo," which offers easier levels tailored to kids for 99 cents.