What You Need to Know About iOS 4

What Is It?

iOS 4 is the newest version of Apple's iOS mobile operating system, the platform used by all models of the iPhone, iPod Touch, and iPad. The major new features (leaving aside the myriad little ones--check out Ars Technica's review for the nitty-gritty): multitasking, iBooks app, threaded emails, Spotlight Search (now supports Wikipedia and web searches), a digital zoom for still photos, and two main UI changes (customizable wallpaper and folders for apps).

If you've updated iTunes...