The same hacker behind the iPad jailbreaking software “Spirit”, and the iPad port of Flash, has released an easy to use jailbreak solution for the iPhone4. Comex and his cohorts have created a website that allows users to complete the job with a single swipe of the finger.
Users of any iPhone model running firmwares 3.1.2 - 4.0.1 and iPads up to ver. 3.2.1 , can go to www.jailbreakme.com , and legally open their phones up to the third-party app stores that lie in wait. When the jailbreak was initially released, there were problems with FaceTime, MMS, and iPad iOS 3.2.1, but those have all been addressed with updates released just hours ago. The server Comex was using to host the exploit was experiencing intense server loads, but Saurik, the man behind the infamous app-store, Cydia, stepped up and offered to donate some server space/bandwidth to the cause.
Before you rush off to the website, be sure to back up all of your data in case the process fails. You stand a very small chance of causing permanent damage, but a small number of people have had to restore their phones/tablets through iTunes. Thankfully, they have been able to retrieve their information, and in most cases, successfully jailbreak after another try.
It would also be a good idea to save SHSH blobs when prompted to do so once you open Cydia. Saving these will allow your phone to downgrade in the future, in case Apple patches the jailbreak exploit with future updates.
Now that the courts have deemed it legal , shake-off the piracy-stigma involved with jailbreaking and discover the world of 3rd party apps in Cydia. There are a bevy of options for customizing your iOS experience. In some cases, you can improve the functionality of your device, breaking free of Apple's restrictions on things like tethering, and backgrounding in 3.1.x firmwares.