MuscleNerd has post a screen-shot of the upcoming version of Redns0w 0.9.9 b5 which will have major update, the Dev-team will merge PwnageTool into Redsn0w.
Jailbreak iOS5 GM with Redsn0w 0.9.9b4
What that means, you will be able to cook your custom firmware from Redsn0w directly which was the major advantage of PwnageTool and Sn0wbreeze. Both PwnageTool (for Mac) and Sn0wbreeze (for Windows) are being used mainly by who rely on unlock for their iPhones as they can preserve the unlockable baseband so they can unlock their iPhones with ultrasn0w. Now Redsn0w new feature will kill the both PwnageTool and Sn0wbreeze for ever, as Redsn0w is always available for both Mac and Windows. The only case that the Dev-team will upgrade PwnageTool is only in case of untethered jailbreaks.
Thanks Dev-team about your continuous hard work and improvements. This is really awesome.