A few months back, Google started testing out a Google Apps feature called 2-step verification. 2-step verification is an opt-in setting that offers added protection for those who aren’t satisfied that a password alone will protect their Google account.
Similar to the way your online banking requires more than one password or code to be entered before you have access to your account, 2-step verification will require those who opt-in to employ a second password in the form of a code that you can either receive from Google (via phone or SMS) or generate yourself on your Android, BlackBerry, or iPhone smartphone. This means that to gain access to your account, a hacker would need both your password and your cell phone to get in. There’ll also be the ability to ‘remember verification for 30 days’ which will mean you won’t have to do the verification-code-phone-dance for a month.
Google is in the process of rolling out this feature so keep an eye out for the 2-step verification link in your account settings.