Facebook Like button stopped working? Try replacing the iframe version with the latest HTML5 version. It'll require an App ID.

Get the Like button code from here: http://developers.facebook.com/docs/reference/plugins/like/

And get the javascript SDK from here: http://developers.facebook.com/docs/reference/javascript/

I found just using the site URL as listed under the App's details will do for the channelUrl - get it here.