Apple on legal iPhone jailbreaks: doing so MAY void your warranty
The company maintains that whether jailbreaks are legal or not, they can still void the warranty on your iPhone. (As Victor Agreda points out at TUAW, "can void the warranty" doesn't mean it always does. We don't know whether there will be exceptions in practice.)
This doesn't change anything, really.
Apple has always maintained that they wouldn't provide support for jailbroken devices, but they've never gone after the folks who publish jailbreaking code or run alternative app stores like Cydia. With 10 million jailbroken iPhones out there, developers who are rejected from the official App Store might increasingly turn to these now-legal alternatives.