Instead of hitting the 'Like' link when liking a thread, you hit the Facebook like button. I made some different colors of this button and a TMS addon for it. Just change the file name in either the folder or the extra.css TMS edit to reflect which color button you want. Uploading my buttons here since the the original thread is closed.
Perquisite: Must have the Template Modification System installed.
Directions: Upload the contents of the Upload folder to your forum root. Install the addon.