Finally, after a couple of months since the release of iOS 4.2.1 we have a untethered jailbreak for the iPad.
It did take longer than expected but thanks to the Chronic Dev-Team we now have Greenpois0n, a untethered jailbreak for iOS 4.2.1.
This tutorial explains how to jailbreak your iPad iOS 4.2.1 using a Mac, click here to view the Windows tutorial.
Before you get started you should plug your iPad into the computer and sync your iPad ( If your iPad is already Jailbroken, restore it in iTunes before using Greenpois0n). Then, quit iTunes and turn off your iPad.