The software for Apple’s (AAPL) iPhone has been cracked; this could lead to a loss in revenue for the company’s wireless partners.

An outfit calling itself the iPhone Dev Team released a free piece of software called “yellowsnOw” that allows subscribers to use the device on any wireless network running the same technical standards.

Software wizards have been trying to unlock the iPhone3G since its launch in July 2007. 

Apple has struck deals with wireless carriers, including AT&T (T), and the customer contract specifies that the device can be used only on those member networks. The new software would allow users to buy time on competing networks when overseas and avoid hefty roaming fees. This is sure to drive Apple’s partners nuts.

Apple doesn’t offer customer support to unlocked iPhones in the US, but is required to do so in Germany and Hong Kong.

Apple declined to comment on the new software. AT&T says use of the unauthorized software would void the phone’s warranty, the Wall Street Journal reports.

The iPhone Dev Team also unlocked the original iPhone. This suggests that Apple may want to hire these guys to make the next model impervious to third party software.

Poor Apple: Beaten by a bunch of geeks who think “yellowsnOw” is clever.