If you're looking to make a drop down menu on your site that looks similar to the Mac OS X pinstripe design, it's fairly easy to do.
First, there is an online demo of this menu here:
The first thing you'll need to do is get all the supporting resource files. On the demo page above you'll see links to about 3 image files. Download these files and place them in your "udm-resources" folder on your site.
Once you've done that, you'll need to replace your current configuration file. First, backup your current configuration file (udm-custom.js in most cases). Then, from the demo page above, download thestyle-pinstripe.js file and save it as "udm-custom.js", rewritting over your previous udm-custom.js file.
That's it. You're menu should now look like the typical Mac OS X style!
(note: OS X is a registered trademark of Apple Computer Inc)