Facebook is moving to a new page plugin that looks like this.
Many websites that have the old like box will be automatically moved to this new plugin. To get this on your site, just go to the Facebook’s page plugin site and fill out the information here. Play with the width and height to make it look right for you, then when you are finished.
Click get code.
You have two pieces of code here. You want to copy the first code snippet.
And paste it in your them header file right after the opening < body > tag.
Then copy the second piece of code.
Then go to your dashboard Appearance — > Widget area.
And add a text widget to your site, paste that second piece of code there.
And click save.
Now you have your like box on your site.