Although Apple only started offering officially unlocked iPhone 4 models in the United States earlier this month, that hasn’t stopped owners from using jailbreak methods to free their devices from AT&T’s clutches and into the waiting arms of T-Mobile, who now claims there are more than a million such users on their network.

9to5Mac is reporting that “over a million” iPhones are actively running on T-Mobile USA’s network, despite the fact that Apple only started offering unlocked handsets here this month. According to a T-Mobile spokesman at this week’s NYC Pepcom event, the majority of that million-plus users are using handsets earlier than the iPhone 4 -- but that a “significant amount” of them had “taken the scissors” to their T-Mobile SIM cards as well.

“T-Mobile doesn’t currently offer a Micro-SIM solution for Apple’s iPhone 4 so people who want to use the iPhone 4 must modify their SIMs into MicroSIMs,” 9to5Mac reports. “Those using iPhone 4s also won’t receive T-Mobile’s 3G or 4G data speeds because of the radio differences between the networks.”

But life may soon get easier for would-be carrier jumpers: The same spokesman claims that Micro-SIMs are “in the works” at T-Mobile, but there’s no word on when that blessed event will occur.

Could T-Mobile USA be officially getting the next iPhone come September? Anything’s possible, especially when there has been some recent evidence to support that an updated version of the iPhone 4 is at least being tested on the company’s GSM network. In the meantime, plenty of you are already rockin’ in a free world on the carrier’s EDGE-based data bands without Visual Voicemail, even though you’ll likely be coming back home next year when AT&T consumes T-Mobile.

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