Greenpois0n 4.2.1 Untethered Jailbreak!

The Chronic Dev-Team released Greenpois0n RC5 that jailbreaks all devices running iOS 4.2.1 untethered. It only works on Macs at this time. This is great considering I got my iPod touch 4G a few days ago with 4.2.1 pre-loaded. The Greenpois0n site isn't working at the moment so you can download RC5 from here. When you jailbreak, it will be the same process as with the 4.1 Greenpois0n except the Loader.app might not work. To fix that, follow this guide.