jQuery.fn.popup = function(options) {
  options = $.extend({
    location:   'yes',
    resizable:  'yes',
    status:     'yes',
    scrollbars: 'no',
    menubar:    'no'
  }, options);
  
  var features = [];
  for (var key in options) {
    features.push(key + "=" + options[key]);
  }
  
  $(this).click(function() {
    window.open($(this).attr('href'), "popup", features.join(','));
    return false;
  });
};

$(function() {
  $('.mailing-list a').popup({ width: 700, height: 760 });
});