Chronic Dev Team has released the first untethered jailbreak for Apple devices running iOS4.2.1.
The hack - which is appears to be available in Windows, Linux and Mac flavours but is currently OSX only - allows iPhones, iPod Touches and iPads running the current version of Apple's mobile operating system to break out of the Cupertino company's walled garden and install third-party apps not approved by Steve Jobs' iTunes junta.
If previous release schedules are anything to go by, Windows and Linux versions will pop up in a matter of days, if not hours.
The exploit used has already been circumvented in the developer betas of iOS 4.3 which, if the frequency of versions being seeded in the past four weeks is anything to go by, is about to drop any day now.
Tethered jailbreaks require the device to be connected to a computer and re-jailbroken every time the power is cycled, and are generally released some time before the untethered versions, which are persistent.
The last time we checked the hacking outfit's ISP was reporting that the download site was off-line, though we can't tell whether it has fallen over due to a sudden rush of jailbreakers (likely given the 502 gateway error) or something more nefarious.