We've previously talked about programmatically liking a post. But I recently tried to like a page, and was presented with this lovely response - "(OAuthException) (#3) App must be on whitelist":
Apparently, you can't like a page via Graph API (or a bug?). You can like a post, but not a page. Very weak! So we're stuck using Facebook's Like Button plug-in (until someone gives me a better idea).