Good news for potential unlockers, PwnageTool, a custom-IPSW jailbreak tool for Macs, was just released, allowing for untethered jailbreaks on iOS 4.2.1 via Mac computers. As many know, custom-IPSW tools are tools that — add — code into your IPSW, legally modifying the OS prior to a restore. The newest PwnageTool adds support for the latest exploit from the Chronic Dev Team, untethering the tethered Limera1n exploit. It also fixes various bugs and includes a patch by comex allowing DRMed books to run on iBooks without Apple’s refusal of it.
The new PwnageTool is available via torrent or through mirror links, one of which is hosted by the author. The link is here: http://mirror.dennisfan.com/pwnagetool_4.2.dmg.
Sn0wbreeze, the Windows equivalent of this tool, was also just updated, potentially for similar reasons (with Pac-Man available while the IPSW is being built).
Currently, the only benefit using these custom-IPSW tools right now over tools like Greenpois0n are for preserving baseband for unlockers, so the rest of you can just head on down to Greenpois0n.com to jailbreak your device much quicker and without restoring.