This blog post is also an article on how to get the Android Device Manager on your Android phone / tablet

In certain circumstances, Google Play services on Android may not show up on Google's Play Store (unless you have its URL). When this happens, on your Android device, uninstall the old version of Google Play services, and then install Google Hangout, or run Hangout if you've already installed it.  Since Hangout requires Google Play services, this will force Google Play services to install.

Once your Google Play services are updated, you will see Android Device Manager when you open up the Google Settings application (which is a green icon with a g and a gear at the top right).

Finally, to access your Android Device Manager online, go to