iPhone Pwnage Project Opens Up Possibilities [Update]
The tool known as "Pwnage Tool" is currently a Mac OS X application that allows users to modify their iPhone's bootloader to allow it to boot any software. In its native state, the iPhone bootloader is what prevents it from booting unauthorized (non Apple) firmware.
Once patched with this tool, the "pwned" iPhone will accept any software to boot, including modified iPhone firmware or alternative operating systems such as Linux. The demo video shows how a custom 1.1.4 firmware that already includes Jailbreaking and Unlocking can be easily loaded onto an iPhone. They also believe the modifications will support future firmware, such as iPhone 2.0, which is due for release in late June.
Early adopters should proceed with caution, of course. While the most common use will likely continue to be unlocking/jailbreaking, the tool opens up many possibilities:
Full independence from Apples vision on what the iPhone (and iPod Touch) can and cannot do.
You will eventually be able to backup your entire phone and restore to a state exactly the way you like it, restore straight to jailbroken state with installer, or even potentially install other OSes like linux (see iphonelinux.org) to your phone.
Update: Delayed until next week.