Earlier today, we reported that Apple had pushed the red button and had sent app subscriptions live for all developers – and just a quickly as they arrived, MacStories now reports that Apple has let loose into the store a number of magazines which feature the new iTunes subscription billing system.

Reported by both AdAge and The Wall Street Journal, Elle and Popular Science are among the first applications to feature to new iTunes subscription system, with more magazines and newspapers bound to follow in their footsteps in the coming weeks.

As noted earlier this month though, they’ll have to be quick as any publication or magazine which doesn’t offer iTunes subscriptions as an option for readers will be systematically rejected from the App Store come Apple’s deadline for integration on March 31.

MacStories notes the process for Elle Magazine below.

We downloaded Elle magazine for a quick test, and it all works pretty much like in The Daily, the first iPad app to adopt subscriptions. Elle offers monthly and yearly subscriptions, provides a round-up of Apple’s rules on the right (see screenshot above) and, more interestingly, comes with a dedicated section for existing subscribers. All you have to do is enter a “special code” to unlock your free Elle subscription for iPad.

[WSJ via MacStories]