The Copyright Office of the United States just allowed iPhone jailbreaking! Quoting from the Electronic Frontier Foundation’s press release (link):

In its reasoning in favor of EFF’s jailbreaking exemption, the Copyright Office rejected Apple’s claim that copyright law prevents people from installing unapproved programs on iPhones: “When one jailbreaks a smartphone in order to make the operating system on that phone interoperable with an independently created application that has not been approved by the maker of the smartphone or the maker of its operating system, the modifications that are made purely for the purpose of such interoperability are fair uses.”

Hell yeah! Common sense: 1. Apple: 0.

To be clear, this doesn’t let you infringe copyright outright – as far as I can tell it is just a DMCA exception. Saurik just demonstrated cydia running on the iPhone 4 (link) – I can’t wait.