According to the latest rumors, Apple intends to establish some ground rules for the applications that will be created with the upcoming iPhone SDK.

According to iLounge, who is quoting a several sources familiar with Apple’s plans, the Cupertino company will distribute the application through its digital hub, iTunes.

As iLounge notes this could be a real advantage for the software developers, because the applications will benefit from iTunes traffic.

On the other hand, in controversial decision, Apple intends to approve all the applications that will made their way on iTunes.

“Our sources confirm that Apple will act as a gatekeeper for applications, deciding which are and are not worthy of release, and publishing only approved applications to the iTunes Store; a process that will less resemble the iTunes Store’s massive directory of podcasts than its sale of a limited variety of iPod Games”, wrote Jeremy Horwitz, Editor-in-Chief of iPod Lounge.

However, other sources, like Electronista, claim that the Apple’s approval will apply only to the commercial applications, while the free ones are not the subject to the same rules. But is still unclear if Apple plans to distribute the free applications through its iTunes.  Electronista said that Apple will reportedly take a portion of the cost of each commercial application.

In addition, iLounge claims that the iPhone SDK will not allow the access to the dock connector, which means that the developers will not be able to develop additional accessories such as keyboards or add-ons.

Also, iLounge noted that at the Thursday’s event, Apple will unveil only a beta version of iPhone SDK, while the final version is scheduled to be released in June at Apple’s WWDC.

Earlier this week, Apple invited has sent invitations to the press for an event that will take place at its headquarters. 

"Please join us to learn about the iPhone software roadmap, including the iPhone SDK and some exciting new enterprise features," reads the invitation sent to reporters.

The Wall Street Journal reports that, according to the analyst Shaw Wu of American Technology Research, the “new enterprise features” could mean a better support for Microsoft’s Exchange and IBM’s Lotus Notes.

But all the speculations and rumors about the future iPhone SDK should be taken with a grain of salt, as Apple didn’t release any official details about its real plans for iPhone SDK.