I recently stumbled across quite an old Internet Explorer position: fixed; workaround which involves some JavaScript. The code allows you to declare the CSS attribute, position: fixed;, on the element of choice as you would normally. The only downside is the requirement of having JavaScript enabled on the clients browser. I came across quite a few of other fixes but this was the only one that actually rendered any results.

Go check out doxdesk.com for an example page as well as the full JS code to put on your site.

For additional discussion on this topic check out tagsoup.com's hack to emulate the CSS 2 positioning scheme position:fixed for Windows Internet Explorer without active scripting.