Sn0wbreeze is considered as the unofficial PwnageTool for Windows. The iPhone Dev Team is about to release the PwnageTool to jailbreak iOS 4.3 of Mac users.
Recently, iH8sn0w just released Sn0wbreeze 2.3b1 for Windows. The Sn0wbreeze 2.3b1 also allows people to jailbreak and unlock their iPhone and to update their iPhone with a pre-jailbroken iOS 4.3 firmware while preserving the baseband from getting upgraded so that it can be unlocked using Ultrasn0w.
Sn0wbreeze 2.3 allows users to create custom iOS 4.3 firmware file that is pre-jailbroken, which can be used to upgrade their iPhone, iPad or iPod Touch to iOS 4.3. If you are using iPhone, it also has the ability to preserve the baseband from being upgraded so that you can unlock it using Ultrasn0w through the “Baseband Preservation Mode,” which is applicable on iPhone 4 users on baseband 01.59.00 or earlier and iPhone 3G/iPhone 3GS users on baseband 05.13.04 or earlier.
The Sn0wbreeze 2.3 supports devices such as iPhone 4, iPhone 3GS, iPhone 3G, Verizon iPhone 4, iPod touch 4G, iPod Touch 3G and iPad. Users will have to use iBooty to boot into jailbroken state (which is installed on your desktop after running Sn0wbreeze 2.3) if for whatever reason they need to reboot their iOS device as Sn0wbreeze 2.3 only supports tethered jailbreak.
The Sn0wbreeze 2.3 is still in beta so expect it to be not in its finest form. t is also important to note that Mobile Substrate is currently broken in iOS 4.3 so jailbreak tweaks such as WinterBoard, Lockdown etc will not work.