Jailbreak iPhone 4S/4 iOS 5.0.1 / 5 / 4.3.5 / 4.3.2 / 4.3 and Preserve Baseband-(Windows)

Jailbreak iPhone 4 and Preserve Baseband
Redsn0w 0.9.9b6 help keep your iPhone 4/3GS baseband when upgrading to iOS 5. To help unlock the iPhone, even after the update to the latest firmware. However, this is only one version of Mac OS X easily. The iPhone Dev Team has come up with Sn0wBreeze v2.8b2 (Windows) that helps keep the baseband when upgrading to the latest firmware.
Preserve Baseband