Apple finally took the step today of enabling two-step verification for the Apple ID. To start, this verification only kicks in when you try to sign in to "My Apple ID" webpage to manage your account, make an App Store purchase from a new device or get Apple ID support from Apple. It doesn't yet work with iCloud.com services including web email which in my opinion still leaves it lacking. However, it's a start.
I was able to activate the service on my account after some trouble. Initially the option to enable two-step verification would not appear in my account after repeated tries in my default browser, Safari. Ultimately I had to log into my Apple ID account with Chrome to get the option to enable two-factor authentication to show up. My guess is Apple is still in process of rolling it out to all users, or perhaps they're experiencing some difficulties as word spreads and thousands of users flock to upgrade their account security. With Apple's history of somewhat spotted history cloud service rollouts, might be a good idea to give this a few days to sort itself out.