If you ever want to steal something in spy movies, you need to tear out somebody's eyeball or fake their voice. AT&T Safe will bring that same level of security to your online accounts with an iPhone app.
Anytime you (or anyone else) tries to access an account, instead of putting in a password, a push notification pops up on your iPhone. You can set how intense the security screening needs to be, but here it requires voice authentication followed by a separate password.
It seems like intense security to lay down on your Twitter account, but my friends already have something similar for their WoW accounts, and given how much personal info Facebook and Google hoard, maybe it's not the craziest idea.