Savvy iPhone users have long beenaware that there's a slew of apps that aren't available through the official app store. These include apps like Cycorder, which lets you use your iPhone as a camcorder or PdaNet, which allows users to use the iPhone's cellular data connection on their computers via a Wi-Fi connection.

All of these apps have been made available through Cydia, a software installer developed by 27-year-old California graduate student Jay Freeman.

In an interview with The Wall Street Journal, Freeman said that Cydia "intends to charge developers no more than the commission Apple does for his site's billing services." The Journal also reported that two more rival app stores are also underway, including one interested in "selling adult games for the iPhone."

While it seems like these App Store rivals may have a court date with Apple in their future, many technology law scholars have said that an Apple legal victory isn't necessarily a given.

The landmark Digital Millennium Copyright Act might offer a means to go after such non-approved installations with, according to this New YorkTimes article,  legal experts not agreeing as to how this uncharted territory could play out. Susan Crawford, a professor at the University of Michigan Law School, said that federal courts ruled that previous DMCA-related cases were less about preventing copyright infringement, but rather about stifling competition. "Courts have said you shouldn't use the DMCA to leverage your copyright monopoly into other markets," she said at the time.

Last December, the EFF proposed an exemption to the DMCA that would legalise jailbreaking. In response, Apple filed their opposition to the proposal in February arguing that it could lead to problems with the iPhone's security and reliability, as well as providing a potential venue for pirated iPhone applications.

Many tech law experts still say that the jailbreakers might actually have a viable defence. While jailbreaking and unlocking are not the same process, the iPhone unlocking process requires jailbreaking, so it seems likely that the same legal reasoning to defend against unlocking might hold. Whatever the case, Cydia's Freeman says he's lawyered up, and is ready for such a challenge.