link_to override

    # Override link_to to link to the facebook app address and 
    # set target=_top when in a facebook iframe, using Facebooker  
    def link_to(name, options = {}, html_options = {})
        if params[:fb_sig_in_iframe]
            rel = url_for options
            url = "http://apps.facebook.com/" + FACEBOOKER['canvas_page_name'] + rel
            html_options[:href] = url
            html_options[:target] = "_top"
            super(name, {}, html_options)
        else 
            super(name, options, html_options)
        end
    end