Checks for the devil of all browsers

iecheck.css

/* could be done using jQuery's .css() function */
#browserupgrade {
	background-color: #f0ffaf;
}

iecheck.js

// lets see what you're running
function iecheck() {
    $(document).ready(function(){
        var $browserupgrade = $('#browserupgrade');
        if (jQuery.browser.msie && parseInt(jQuery.browser.version,10) <= 6) {
            var message = 'Ahoy hoy! You should download <a href=\'http:\/\/www.google.com/chrome/\'>Chrome</a>, <a href=\'http:\/\/www.getfirefox.com/\'>Firefox</a>, <a href=\'http:\/\/www.apple.com/safari/\'>Safari</a>, or <a href=\'http://www.opera.com/browser/download/\'>Opera</a>.';
            $($browserupgrade).html(message).after("<br />");
        }
    });
}