It was just a matter of time until the iPhone 4 would get its now DCMA-permitted jailbreak to allow users to install software without having to get Apple's approval first.
Now just after the iPhone 4's worldwide launch in 17 more countries, Comex along with other iPhone hackers have released one of the easiest jailbreaking methods to date – a method that requires the user to simply visit a web URL to start the process.
Those with any iPhone or iPad can just hit http://jailbreakme.com/ and it'll jailbreak the device without a need for any PC or Mac intervention.
Earlier versions of JailbreakMe had a few bugs that led the MMS and FaceTime being disabled, but those have since been rectified. Those who still have the MMS and FaceTime issues should update Cydia and reset network settings.