A few days ago the dev team released redsn0w 0.9.15b2 an addition that added many new features including re-restoring and Cydia support for iOS 6. Today, the dev team released yet another update, this time to fix bugs seen when used with the iPhone 3GS and iPad. Other than the small changes everything is the same and tethered for every device except iPhone 3GSs with old bootroms. We reccomend that you download the new software at the bottom of the post if you had any problems jailbreaking iOS 6.
Dev Team Blog
Version 0.9.15b2 fixes a few issues for 3GS owners: old-bootrom awesomeness is no longer forgotten directly after a restore, and iPad baseband upgrade/downgrade support is fixed (same production date cutoffs apply!). If your 3GS is currently tethered at 6.0 even though you have an old bootrom, just re-run redsn0w’s Jailbreak step (no need to restore). Don’t forget you can add some pizzaz with your own boot logo or a nerdy verbose boot.
Download For Mac
Download For Windows ( Make sure to Run as Administrator!!!!!)