Dev-Team has just updated their popular jailbreak tool Redsn0w which supposedly addresses certain issues plaguing the OS X users. The latest release is Redsn0w 0.9.10 b6b which has been pushed out for OS X only and does not add any jailbreak support for iOS 5.1, tethered or untethered for current A5 devices.
However, like the previous version, this one also supports a tethered iOS 5.1 jailbreak for non-A5 devices i.e iPhone 3GS (new bootrom), iPhone 4 and the original iPad. Owners of iPhone 3GS with older bootrom can enjoy untethered jailbreak on iOS 5.1. You can follow our step-by-step guide on how to use Redsn0w here.
According to the Dev-Team blog:
Update #1b: The OS X version of redsn0w has been updated to fix an issue for those running OS X 10.5.x or earlier.
Below are the official download links: