Redsn0w is a cross-platform jailbreaking, unlocking, and customizing tool for iPhones and iPod touches. With Redsn0w you can mod the iPhone your way. It includes customizations of boot logos, recovery logos, and “verbose” boot.
Today, the final version of Redsn0w, v0.9.2 for Mac and Windows was released.
For more information on Redsn0w go here.
Download links for Redsn0w for Windows and Mac: