Hi there,
Here is the BBCode for a Facebook like button.
BBCode usage
Quote[fblike]{URL}[/fblike]
HTML replacement
Or
You can use {LOCAL_URL} instead of {URL} if you want it only relative to the topic page.
P/S: Thank for your idea, [URL="http://www.freeforum.ca/forums/members/ramook.html]ramook[/URL]