Until today, one distinguishing feature of all “smartphones” has been a physical QWERTY keyboard with tiny fixed keys. On the most popular smartphones, like Treos and Blackberrys, the keyboard takes up about one-third of the front of the phone, leaving space for other buttons and a small display screen. Other phones, like Helio’s Ocean, are “transformers” that slide open to reveal full fixed-key keyboards and larger display screens. Whatever the configuration, smartphones need a keyboard users can type emails, SMS messages, and web addresses.

Apple’s iPhone uses a keyboard as well, but with a unique approach. There is but one physical button on the face of the iPhone – a “Home” button that can bring you back to the phone’s main menu. All of the iPhone’s many features are accessed by touching a large (by smartphone standards) high-resolution screen. When you need a keyboard, the iPhone presents a “virtual” keyboard on the screen. You select letters and numbers by touching the screen.

Unlike other smartphones with fixed keyboards, the iPhone’s keyboard changes to fit the task “at hand” (sorry, I couldn’t resist). For example, when composing an email message the keyboard is “straight” QWERTY. However, when invoking the keyboard to type a web address into iPhone’s Safari web browser, a slightly different keyboard appears. Because you don’t use spaces when typing URLs, the Space Bar is replaced by special keys relevant to web browsing. Like a dot, a forward slash, and a key that types “.com” for you. Sweet.

The iPhone’s keyboard is more than just good looking – it’s smart too. It incorporates advanced technologies to correct and prevent mistyped words, constantly analyzing your keystrokes to suggest words as you type. It contains an entire English dictionary, and learns the words you type most often, including proper names and everything in your Address Book. That’s right. You start to type the name of someone in your Address Book, and the iPhone offers to complete it with one more keystroke (the Space Bar, to be exact).

iPhone also employs complex mathematics to improve your typing accuracy by tracking the pattern of letters you type, and matching them to the pattern of other common words. Say you’re trying to spell “cat” but your pudgy finger accidentally hits the virtual “y” or “g” key adjacent to the letter “t”. iPhone knows that “cay” and “cag” aren’t common words and goes ahead and types “cat”. Wow.