These fixed elements have been popular recently, most famously the bar on the bottom of facebook that remains in place no matter where you scroll on the the site. Other sites, such as this one, use it to have a convenient twitter link; the uses are endless.

First, the CSS code:

#fixed_div {
 position: fixed;
 top: 150px;
 left: 0;
 width: 100px;
 height: 15px;
 background: #000;
 margin: 0px;
 padding: 2px;
}

This will fix an element along the left side of the page, 150px from the top of the browsing window.

Now the HTML code:

<html>
<head>
 <title>test page</title>
</head>

<body>
 <div id='fixed_div'>
 This is some floated text
 </div>
</body>
</html>

Other CSS properties will work for this system too:

top right bottom left

Ex. Position box at...

 left side:  top 0    left 0
right side:  top 0   right 0
    bottom: left 0  bottom 0

Basically when you define top, left, bottom, or right, whatever number (in px, em, etc) you supply will be that far away from the top, left, bottom, or right (e.x. right: 200px will put the item 300px away from the right border of the browser)

Play around with the values in order to get the layout you desire. If you have any questions, post them in the comments below