There are more elegant ways to achieve floating effects, but the advantage of this code is that it works in IE6,7,8, FireFox, and Google Chrome. (It really works brilliantly in Chrome, as smooth as it gets)
Notice how the Quick Launch menu scrolls with the content
Follow the steps outlined below to implement the changes on your site collection:
Download and install Muhimbi’s SharePoint Infuser on one of your Web Front End Servers.
Ensure you have Designer privileges, more specifically the Add and Customize Pages right.
From the Site Actions / Site Settings screen, select Infuse custom content in the Look and Feel column.
Copy the script at the end of this posting and paste it into Infuser’s code window. If you are using IE then you may want to paste it in WordPad first , otherwise all line breaks are stripped out.
Click the Save button and navigate to any page that is long enough to have a scroll bar and scroll the window down.