1. First COPY the Facebook code below.
<div style='float:left;margin:4px;'><iframe allowTransparency='true' expr:src='"http://www.facebook.com/plugins/like.php?href=" + data:post.url + "&layout=standard&show_faces=false&width=100&action=like&font=segoe+ui&colorscheme=light"' frameborder='0' scrolling='no' style='border:none; overflow:hidden; width:400px; height:27px;'/></div>
2. Login to your Blogger Account and go to Design > Edit HTML and click on the check box which says “Expand Widget Templates”
3. Look for <data:post.body/> and immediately PASTE before that place the copied code.
4. Save the template and you should see the Like Button near each of your posts. You are done :)
Source : Blogger Plugins