Today I enabled 2-step verification in Google Apps. This means that if you want to you can use 2 factor authentication when logging in to Google Apps services such as GMail. You can’t force your users to use 2-step verification, they must opt-in themselves.
Anyway, I did opt-in with my account and downloaded the Google Authenticator to my Android that is used for generating codes. It all work well and now I’m using 2-factor authentication for my Google account.
When you want to opt-in for 2-factor authentication you can follow this step by step instruction that is available at Google.