Apple is to block developers’ abilities to distribute iPhone applications outside of its iTunes App Store.

Developers were previously allowed to distribute apps directly to users by binding the software to the serial number of their iPhone.

The move is certain to add to the growing disquiet from application developers unhappy with Apple’s unclear and seemingly arbitrary approvals policy.

A number of apps, including Podcaster, NetShare, Murderdrome and MailWrangler, have received rejection letters from Apple despite following official guidelines.

Among those affected by the latest decision is Almerica, the creator of a podcast download and playback tool known as Podcaster.

It was initially rejected by Apple because the application duplicated the functionality of the Podcast section of iTunes.

So it began using a method that created ad hoc licenses for the utility as an impromptu distribution tactic, an approach that left out the App Store entirely and consequently left Apple out of its 30 per cent revenue from each sale.

The new restriction is being seen as a risky precedent and one that could lead to legal activity if Apple’s attempts to control any and all sales channels of software to iPhone and iPod touch owners falls foul of monopoly legislation.

Apple is also trying to prevent developers whose applications are rejected from discussing the reasons by issuing a non-disclosure agreement with the refusal notice.

The situation is in stark contrast to T-Mobile’s G1, which as the first official Google Android phone operates an open source policy for applications and OS development/modification.

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