Ah, the App Store, what would we do without your dramas? Fresh off the Google Voice debacle, all eyes turn again to the mysteries of the App Store approval process as Vonage finds their app in limbo awaiting approval.

While Skype seems to have no trouble working on the iPhone, it appears that AT&T and Apple have come to some agreement regarding VoIP technology piggybacking on any of the the carriers cellular bandwidth. As Skype is mostly used for Skype to Skype calls, they appear to fall within a gray area for both companies.

However, enter Vonage. 

For several years now, Vonage was one of the leading providers of VoIP. Much of their business model centered around the ability to make calls from your Vonage number to landlines as part of their regular service offerings, something Skype only offers for a fee. A limited service such as Skype, one available only between Skype users is one thing.

The opening of competition to AT&T's telephony service through VoIP that regularly contacts landlines, however? The use of AT&T's 3G cellular network is likely to prove a roadblock to Vonage's app being approved. Indeed, enabling the service for anything other than Wi-Fi users might just go against the two companies' contractual arrangements, as spelled out in this letter from the carrier to the FCC:

…The parties’ willingness and ability to assume the risk of their investments in the iPhone and of their pricing strategy were predicated, in significant part, on certain assumptions about the monthly service revenues that would be generated by iPhone users. In particular, both parties required assurances that the revenues from the AT&T voice plans available to iPhone customers would not be reduced by enabling VoIP calling functionality on the iPhone. Thus, AT&T and Apple agreed that Apple would not take affirmative steps to enable an iPhone to use AT&T’s wireless service to make VoIP calls.

While Apple spokeswoman Natalie Kerris explains that the Vonage app is being reviewed for some technical issues, we're not entirely certain we'd hold out hope for a speedy approval. Skype's one thing, as small as it is. Vonage takes the game to a whole new level of competition. Unless they retool for WiFi use only, the smart money's on Vonage getting a rejection letter soon.