Have an unlocked iPhone that you want to keep using? Don't install the new Apple firmware update (1.1.1) -- at least not yet!
It's a big ol' game of cat and mouse and Apple just re-took the lead. iPhone firmware version 1.1.1 came out today, and it adds a bunch of features to your iPhone free of charge. Unless, that is, you're using an unlocked iPhone, in which case it re-locks the phone and (as of late Thursday afternoon) leaves it in a useless state of de-activated limbo. According to reports around the Web, unlocked phones get reset to the activation screen but cannot be subsequently activated. So they're not exactly bricked, but not exactly usable in any way.
Apple warned everyone that they wouldn't be looking out for unlocked handsets and unauthorized apps when it came to iPhone software updates, and they weren't lying. The newest firmware locks handsets back to AT&T and disables third party applications even if your phone is still locked to AT&T.
Rest assured iPhone hackers have already mobilized to put together a counter-punch to enable unlocked iPhones to reap the benefits of firmware 1.1.1. What benefits, you ask? How about the iTunes Wi-Fi Music Store, louder volume on calls, double-click shortcuts on the Home Button and Space Bar, and TV Out support, to name a few.
If you've got a "legit," locked to AT&T, never hacked in any way iPhone, go ahead and get yourself that software update. If you're using a modified iPhone, you'll want to hold off until a workaround is developed ... I'll let you know as soon as I hear about one myself.