While iOS 4.2 didn't bring all it promised (ahem, AirPrint), here's a look at all the major new features, how they work, and how to enable the ones that don't.
AirPrint
There has been a whole bunch of trouble over AirPrint lately, with Apple pulling AirPrint support from Mac OS X 10.6.5. What the feature was supposed to do is allow you to print a document or photo from your iOS device to any shared printer on your home network. Without support in the desktop operating system, this is pretty hard to do. If you're on a Mac, however, you do have some options to get that support back. The easiest way is to just install the missing files. Here are instructions on how to do that, or you can use AirPrint Hacktivator to automate the process. If you don't feel like modifying your system, want a GUI, and some added functionality, check out Printopia and Fingerprint ($10 and $8, respectively). They enable AirPrint support on your Mac with a friendly interface.
If you're not a Mac user you're not barred from printing from your iOS device. Here are some tips on printing from your iOS device without iOS 4.2 if you really want the feature but don't meet one or more of the numerous requirements to get it to work.
AirPlay
AirPlay is basically a repurposing of the previously existing AirTunes technology Apple's always included, letting you stream music from your iOS devices to an AirPort Express or AppleTV. The reason the name has changed, however, is because you can stream not only your music but video as well to AirPlay-compatible devices. At the moment, the AppleTV is the only device to which you can push video and, thanks to the latest Apple TV update (also released today), it works beautifully. Streaming is remarkably fast and any video encoded to Apple's specs will stream just fine. Check out the video above for a demo.
Find My iPhone/iPad/iPod touch — For Free!
While it would be especially nice if Apple would make MobileMe a free service for all, they've taken the baby step of enabling one of its better features—Find My iPhone—for all iOS users. Even if you don't pay for MobileMe, you can now use Find My iPhone (or iPad or iPod touch) for free. If you're not familiar, the service basically does two things: it helps you locate a lost iOS device or lock down your data if your device is stolen. You still turn it on in MobileMe preferences, but now it just doesn't cost you anything. In the event you lose your iOS device, you can use one of your other iOS devices or the MobileMe web site to track it or lock it down.
iPad Multitasking
Multitasking is a feature we've had since iOS 4 on the iPhone and iPod touch, but it's generally agreed that it's been sorely missed on the iPad more than anywhere else. Multitasking on an Apple device isn't necessarily true multitasking, but it allows you to switch between open applications without returning to your home screen. Developers are also able to suspend their apps while in the background and allow certain operations, such as audio playback, to continue even after leaving the app. This is great for fans of Pandora radio, or other music services, who want to listen in the background while answering email, browsing the web, or doing anything else on their iPad.
iPad Folders
Just like with multitasking, folders have come to the iPad in iOS 4.2. Now you can tap and hold down an app, drag it to another app, and create a folder on your iPad. It works about the same as it always has in iOS 4 on the iPhone and iPod touch, but the maximum app limit is 20. While not particularly new, this is a very welcome feature on the iPad if you have way too many apps and need a way to organize them.
Want all these new features? iOS 4.2 is due for release at 10:00 AM Pacific, today, right now. Plug in your iOS device, open iTunes, and get ready to update.