Apple has begun rolling out iOS 4 (formerly known as iPhone OS 4.0) to the public. This latest firmware release finally comes with multitasking support as well as providing users to customize the homescreen wallpaper and a host of other new features. iOS 4 is compatible with both the iPhone 3G and iPhone 3G S though certain features such as multitasking are limited to the latter model.
In related news, ultrasn0w 0.93 has also been released which not only unlocks baseband 05.12.01, but more importantly, also works on the new baseband 05.13.04 used by iOS 4. You can find this latest iPhone unlock tool by adding repo666.ultrasn0w to your repo in Cydia. Of course, you do need to jailbreak your iPhone first in order to do this and there’s also an appropriate jailbreak tool now available as well depending on your iDevice. If you own an iPhone 3G, you can use the updated redsn0w beta release to jailbreak it. For iPhone 3G S owners, there’s the iOS 4 GM jailbreak bundle for PwnageTool you can try out to help you get a jailbroken version of iOS 4 installed on your iPhone.
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UPDATE: PwnageTool 4.0 is now available which can be used to jailbreak the official iOS 4 update from Apple. You can read more about it here.