Version 0.9.15b3 fixes the redsn0w “error 2601” that Windows users were seeing using the Restore button. It also fixes a related Windows iTunes error 14 for stitched files. Note that if you have a baseband, you should probably avoid stitching and simply use redsn0w’s native Restore (not iTunes).
Those lucky recipients of new iPad minis and iPad4s on Friday can use this redsn0w to save your 6.0 blobs off to Cydia. First connect your new device and turn it on, then use redsn0w’s Extras->SHSH Blobs->New and point it at the 6.0 IPSW.
Expect an ultrasn0w compatibility update for iOS 6.0 by Friday (mostly useful for 3GS old-bootrom users who are currently enjoying the untethered 6.0 jailbreak!). Same baseband support as with 5.x.
Thanks to @iamgolfy for helping test the 2601 Windows fix!
You can download the latest version of RedSn0w from here.