Earlier this week, we told you about . Now that is over, how did Apple do? Here's a quick scorecard.

Of course, it's important to keep in mind that the progress we've noted below is based on a single overview of iPhone OS 4, months before it's ready to go--Apple may end up adding to these features, as well as adding many other features, by the time iPhone OS 4 is released.

We wanted a way to let apps function in the background; heck, we said we'd be happy with a way for apps to better save their state or a way to more quickly switch between, say, the most recent two apps. We've also hoped for audio apps to be able to stream content in the background. Based on today's preview, iPhone OS 4 . You'll be able to keep multiple apps running and then switch between them using a new "app-switching dock." Audio apps will be able to play in the background, and they can even utilize the iPhone's pop-up playback controls (the ones you see now if you double-press the Home button while the iPod app is playing). iPhone OS 4 will also provide developers with better APIs for saving an app's state so the app doesn't use any resources when not active, but it can be immediately up and running when you switch back to it. And apps that need to finish a lengthy task, such as uploading photos to the Web, will be able to finish those tasks in the background and then gracefully exit.

But there's a lot more: Apps such Skype will be able to watch for, and notify you of, incoming calls even if you're working in another app or the phone is locked and asleep. Apps that use your location will be able to use the iPhone's Location Services API even when the app is in the background, so, for example, a GPS app can continue to provide voice directions while your kids watch a movie in the back seat. Alternatively, if an app doesn't require pinpoint location accuracy, the developer can instead use a new energy-saving background service that uses mobile-phone towers to determine your location. Finally, another new multitasking feature, Local Notifications, allows applications to notify you of events without needing to contact Apple's notifications servers; examples include a TV-listing app that notifies you before your favorite show is about to start and an alarm-clock app that can wake you up without you having to keep the app running all night.

The one omission we noticed was a way for a background process--say, an instant-messaging or Twitter client--to poll for new messages; based on Apple's answers to questions after the event, the company feels that using the existing notifications feature (see below) is sufficient. In other words, almost everyone got what they wanted--or at least of bit of it. --Dan Frakes