You won't get the new iPhone 4 until Thursday, but you can download Apple's new iOS 4 operating system for the iPhone 3G and iPhone 3GS, and second- and third-generation iPod Touch models — if you can get through, and if the system doesn't clog up.
The new operating system, made available June 21, has features like multitasking, so, for example, you can check e-mail while playing Pandora radio or other third-party music apps; "smart" folders for grouping apps by topic; and unified e-mail so you can see all your e-mails in one list (vs. switching between e-mail accounts).
It also includes Apple's recent iBooks program, first shared on the iPad, which will let you sync your books and PDFs between Apple devices. You will also be able to buy books through iBooks for the iPhone or iPod Touch.
Those with the first-generation iPhone and iPod Touch, which both came out in 2007, will not be able to use iOS 4 because hardware on those devices won't support the new operating system, Apple said.
iOS 4 is free for all compatible devices, and can be downloaded via iTunes 9.2 or later. If you're not sure which iPod Touch model you have, the second generation came out in the fall of 2008. The third generation includes only the 32GB and 64GB models that shipped in late 2009. (The 8GB $199 version is considered second gen.)
The iPhone 4, which goes on sale Thursday, will come with iOS 4, which was first previewed on April 8 by Apple CEO Steve Jobs, two months before he announced the new iPhone.
The "i" in the revamped name of the operating system signifies the unification of the OS for Apple's mobile devices.