Apple's unloading iOS4 (that's the new name for iPhone OS, in case you didn't know) tomorrow, which means you should get started tonight.

A Gold Master release of iOS 4 (née iPhone OS) was seeded to developers yesterday. And the next iPhone's software has been surprisingly accommodating to jailbreakers' attempts to crack it wide open.

The Apple iOS 4.0 Gold Master has hit the iPhone Developer Center and we're tearing it apart to find out what's new so that you don't have to risk your iPhones. Here's what we've discovered so far.

The Apple iOS 4.0 (formerly referred to as iPhone OS 4.0) has gone gold master and is available to iPhone developers now. We'll do our usual rundown of what's new soon, so keep an eye out. [Apple]

It's about time that the iPhone gets a custom dictionary, and according to this screen from the latest iPhone OS 4 beta, you'll find one under keyboard settings. Duck yes! (Discover more recent iPhone OS 4 findings here.)

Oh yes! iPhone OS 4.0 Beta 4 is out and we're tearing it apart to find out what's new so that you don't have to risk your iPhones. Here's what we've discovered so far. Updated.

Given surging popular sentiment-that-will-not-amount-to-anything, this might make you feel ickier, rather than happier, but the rumor is that deep Facebook integration with the iPhone is actually happening.

Attention, developers! Apple's got the third beta of iPhone OS 4.0 and its SDK available for download here. No word yet on what's changed from the previous release, but if you're registered with the iPhone Dev Center, get to it. If you're one of the rest of us, the official public release is expected this summer. …

Multitasking! On phones! Everybody does it now. But each smartphone platform does it differently. Here are the various tricky ways that the major platforms try to juggle multiple apps.

Code trickles promised video chat hiding inside iPhone OS 4, raising hopes and inflating sci-fi fantasies. Now code snippets bring us back to earth, that iPhone video calling might be real but only over Wi-Fi.

There's a lot to be happy about in iPhone OS 4. Like multitasking, and threaded inboxes. So why doesn't it feel right?

Car kits for iPods and iPhones aren't exactly big news, with plenty of third party accessory companies feeding off the ecosystem already. But an Apple-branded kit, found buried in iPhone OS 4?

Obsolescence, meet iPhone. It's true, iPhone OS 4 won't touch the original iPhone at all. But even the iPhone 3G is getting shafted quite a bit with iPhone OS 4.

Popups were an understandable workaround for the shortcomings of the iPhone operating system. But with OS 4, Apple missed their chance to build a good alert system. Now, popups are about to get way out of hand.

Though iPhone OS 4's real potency will come when developers seize the new tools and build multitasking apps that do crazy, crazy things, many of the OS's inherent secrets are coming to light. Updated: More secrets.

9to5Mac dug up references to video conferencing—hosted on Apple's own servers—as well as group chat rooms and chat moderators in iPhone OS 4. That's good news.

Steve Jobs, personal email replier he is these days, responded to a message from a developer regarding this week's SDK kerfuffle. His (characteristically brief) take: "intermediate layers between the platform and the developer ultimately produces sub-standard apps."

Apple's move to ban Adobe's Flash-to-iPhone compiler elicited shrugs from Adobe and complaints from Adobe loyalists. Digging deeper into the OS reveals another, albeit less dramatic slight: Apple scrubbed Google's name from the new OS's Safari search button.

When Jobs announced multitasking for iPhone OS 4, everyone got giddy... until Apple said that this important feature wouldn't work in older iThingies because of "hardware limitations". The hardware, however, fully supports multitasking. Why not enable it, then, Apple?