It hasn’t even been released to the public yet, but Apple’s upcoming iPhone OS 4 update has already been jailbroken.
The jailbreaking tool is in beta itself, and the people behind it are warning the average iPhone user to tread carefully:
Please note that this beta is not meant for the average end-user. There are many things “broken” with jailbroken apps in the 4.0beta1 environment right now [...] This beta redsn0w allows the developers behind those jailbroken apps (like MobileTerminal.app!) to fix their software before the general public gets iphoneOS 4.0.
Because it’s meant for JB app developers, this beta redsn0w does not perform hactivation. You’ll need a properly-registered developer UDID with Apple to get past the activation screen. For similar reasons, there is no Windows version of this beta redsn0w (since apps are developed on MacOSX). Please don’t pirate Apple software.
So, for those of you that do jailbreak your iPhones–it’s probably a safer bet to just wait. As Mashable points out, there will likely be a more consumer friendly tool closer to the launch of OS 4.