[Dorian_bs]

Я знаю, что "вконтакте" подобная проблема решена. Вот часть их скрипта.
Тут при наведении мышки изменяется цвет фона кнопки

var close_button = ge('im_x');
    var popup_button = ge('im_popup');
    var sound_button = ge('im_sound');

    var fadeToColor = function(color, master) {
      return function() {
        this.fading = master ? true : false;
        animate(this, {backgroundColor: color}, 200);
      }
    }
    addEvent(close_button, 'mouseover', fadeToColor('#FFFFFF'));
    addEvent(close_button, 'mouseout', fadeToColor('#9CB8D4'));
    addEvent(close_button, 'click', im.popup ? function() { window.close(); } : winBoxes.im.hide);
    if (im.popup) {
      hide('im_popup_button');
      im.fix_popup();
      addEvent(window, 'onorientationchange' in window ? 'orientationchange' : 'resize', im.fix_popup);
    } else {
      addEvent(popup_button, 'mouseover', fadeToColor('#FFFFFF'));
      addEvent(popup_button, 'mouseout', fadeToColor('#9CB8D4'));
      addEvent(popup_button, 'click', im.go_popup);

      if (window.im_check) {
        winBoxes.im.setOptions({onHide: function() {
          window.im_ts = im.ts;
          setTimeout(window.im_check, 1000);
        }});
      }
    }
    addEvent(sound_button, 'mouseover', fadeToColor('#FFFFFF'));
    addEvent(sound_button, 'mouseout', fadeToColor('#9CB8D4'));
    addEvent(sound_button, 'click', function() {
      if (im.sound_off) {
        im.sound_off = false;
        ge('im_sound').className = '';
      } else {
        im.sound_off = true;
        ge('im_sound').className = 'off';
      }
    });