homepage

Something like this maybe?
div.sphinxsidebar {
 float: left;
 width: 230px;
 height: 100%;
 font-size: 90%
 /* add these: */
 margin-top: 30px;
 height: 100%;
 overflow: auto;
 position: fixed;
}
...
div.related {
 background-color: #133f52;
 color: #fff;
 width: 100%;
 line-height: 30px;
 font-size: 90%;
 /* add this: */
 position: fixed;
}
I tested it only with Firefox3 and the Webdeveloper plugin and it looks
ok. "position: fixed" doesn't work on IE6 and there could be other
problems, but it may be a good starting point.