Total Posts: 1395
I just had a look at the AddThis.com share thing. It seems fairly easy to integrate. When you register for an account, select the options you like then hit the "Get Your Code" button, this will give you the html/js code you need to add the buttons to your site.
Edit whichever template you're using in the news system via Optiosn > Templates >
Expand the "Comments Structure" section and paste the html/js code that was given to you wherever you want the AddThis buttons to appear. Now when viewing a full article it'll display the buttons.