Facebook Like Button

You are able to add a Like button which likes a given URL (static, e.g. your homepage) or/and put a dynamic Like button on your page to like the page you are actually visiting. The module add also a share button.

Install and enable the module.

ShareThis

The module ShareThis integrate social bookmarking utility on the node types you want.
Download and enable the module.

Go to Configuration - Web services - ShareThis

Choose a button style.