Reflection.js

http://cow.neondragon.net/stuff/reflection/
"Reflection.js 1.6 allows you to add reflections to images on your webpages. It uses unobtrusive javascript to keep your code clean.

It works in all the major browsers - Internet Explorer 5.5+, Mozilla Firefox 1.5+, Opera 9+ and Safari. On older browsers, it'll degrade and your visitors won't notice a thing. Best of all, it's under 5KB."