Google has begun rolling out an update to its Google Play Services that includes the ability to remotely change your phone unlock password--a major addition since the search giant released the Android Device Manager last month. Now you'll be able to lock your Android phone remotely, rather than having to completely wipe it before you can get to it.
Google announced the Android Device Manager as a way to help you track and locate any Android devices associated with your account without having to install a third-party application, but glaringly omitted the ability to remotely lock or change your password. The services won't work if the phone is turned off, but you can select an option to have the phone wipe itself if you mark it as missing and it's turned back on again.
Google is slowly rolling out the feature via its Google Play Services. You can check to see if you have it by going to the Device Administrators panel under the Security section in your settings.