Multitasking gestures are multi-touch, which means you use four fingers to activate them. Once you turn them on, these gestures carry out specific functions that help the multitasking features of the iPad become more fluid.
Switching Between Apps. The most useful of the multitasking gestures is the ability to switch between apps by using four fingers and swiping left or right on the screen. This means you can have Dragon Dictation open and easily switch from it to a word processor or a website, thus allowing you to easily dictate text instead of tapping it onto the iPad's onscreen keyboard. Remember, you need to have recently opened at least two apps for this to work.
Getting Back to the Home Screen. If switching between apps is the most useful, getting back to the home screen will be the most used. Instead of clicking the home button, you can use four fingers to pinch in on the scree, just as you might use two or three fingers to pinch in when trying to zoom out of a website or picture. This is nice because sometimes the iPad gets turned around and the home button is on top rather than the bottom. Rather than looking for it, you can just get used to doing this gesture.
Bringing Up the Task Bar. A very useful feature that is often overlooked, the task bar can be used to switch between apps, close apps completely -- which is handy if your iPad is running slow -- or control your music playback by swiping right to bring up some music controls. Normally, you bring up the task bar by double clicking the home button, but with mulitasking gestures, you can pinch out with four fingers just as you might zoom into a webpage or picture when pinching out with just two or three fingers.
With the ease of manipulating the iPad using these gestures, it's easy to see a version of the iPad that does away with the home button completely, as has been rumored in the past. And once you are accustomed to using these gestures, you might never miss the home button.