Yesterday marks the release of the 3rd 'userland' jailbreak for the iOS family. A userland jailbreak allows an iOS user to install Cydia (the hack app store) by simply visiting jailbreakme.com. So all those awaiting your pre-sale Mimics can get ready for your install by just visiting that link and downloading the "Mimics Driver" app from Cydia.
This jailbreak is good for anyone using an iPhone, iPod touch, iPad or iPad 2 running the latest 4.3.3 firmware. If you aren't on 4.3.3, feel free to update as normal in iTunes, even if you are already jailbroken and just wish to update. Note: you will want to back up your Cydia apps if you are upgrading from a previously jailbroken device. As always, backup your phone with iTunes before jailbreaking.