scroll avanzado

scroll_avanzado.html

<style>
.window_scroll{
    display:block;
    width:100%;
    height:100%;
    overflow: hidden;
}

.window_aside {
  display:block;
  width: 173px;
  height: 100%;
  float:left;
  position:relative;
  font-size: 11px;
}

.window_main {
  display:block;
  overflow: auto;
  height: 100%;
}
<!--
aqui esta en fiddle http://jsfiddle.net/punktoy/e5Mvc/
-->
</style>
<div class="window_scroll">
<div class="window_aside">
aqui no escrolea
</div>
<div class="window_main">
aqui escrolea
</div>
</div>