Two-factor authentication is one of the best things you can do to secure your online accounts. Today, Microsoft is rolling out this important feature for Microsoft accounts — the key to Outlook.com, Windows 8 PCs, SkyDrive, Skype and Office. Here's how to enable it on yours.
Head over to https://account.live.com/proofs/Manage and sign in to your Microsoft account. Then click on the "Set up two-step verification" link to secure your account and make it harder for hackers to take it over with a stolen password. Then on the Security info page, add your mobile phone number and an alternative email address.
As with other places, you should have two-factor authentication turned on, when you sign in to your Microsoft account from an unknown device, Microsoft will send you a code you'll have to enter before letting you in. You can have Microsoft remember your device for 60 days, so you don't have to keep entering codes.
Note that the feature is still rolling out, so you might want to wait a little while before you see the option to turn this on.
Finally, Microsoft is also offering a Microsoft Authenticator app for Windows Phone. See Microsoft's blog for more details on the new two-step verification.
Microsoft Account Gets More Secure [Official Microsoft Blog]