The GreatShield EZseal Plus is one of four "bubble-free" screen protectors we have on the list. They're all very similar and share one common trait: only the outer frame adheres to your iPad and the middle of the protector doesn't actually stick to the screen (which is why you don't get any bubbles). You just clean your screen carefully, align the protector on top of your iPad, lay it down, and you're done. If you don't get it right, you can always pull off the protector and start over.
However, there's one big caveat. This screen protector -- and others like it -- will slightly reduce the clarity of the iPad 3's display.