Just read this on Arstechinica. Apparently jaibreaking an iPhone is legal for now but not the iPad or other tablets.
The new rules allow circumvention of "computer programs that enable wireless telephone handsets to execute lawfully obtained software applications, where circumvention is accomplished for the sole purpose of enabling interoperability of such applications with computer programs on the telephone handset." In other words, jailbreaking is permitted for "telephone handsets," as it was under the 2010 rules.
What about tablets? No dice. The Librarian "found significant merit to the oppositions concerns that this aspect of the proposed class was broad and ill-defined, as a wide range of devices might be considered 'tablets,' notwithstanding the significant distinctions among them in terms of the way they operate, their intended purposes, and the nature of the applications they can accommodate. For example, an e-book reading device might be considered a 'tablet,' as might a handheld video game device or a laptop computer."