splash Masque Clear Screen Protector for iPhone 4 4G  4S AT&T and Verizon (3-Pack + 2 Bonus Back Films)
Great screen protector. Easy to install. Totally invisible. You can't even tell it's there. Looks and feels just like the actual screen. The only drawback I have found is that it shows fingerprints a lot. But it's easy to wipe off.