Load up the object that you want to apply this effect to. If you are familiar with “symbols” I really recommend converting the object to a symbol. That way if you have to make a change to the original object you only have to do it once.
The following is the object that I chose. This is a bitmap object but you can use any vector object as well.
Click on your object with the Pointer Tool to select it. Clone the object by pressing CTRL + SHIFT + D. Now go to the Modify menu and choose Transform and then Flip Vertical. Finally, move your flipped object so that it is lined up with the bottom of the original. Your image should look like the one below.
Using the Skew and the Scale tools you can give your object a little distortion to make the relfection a bit more believable. In my example I skewed the bottom outward and scaled the bottom upward. This step is optional.
Here’s what my example looks like after the distortion.
With your flipped object still selected go to the Commands menu and choose Creative and then Fade Image. Choose the far right Top to Bottom fade and click OK. See example below.
Your image should look similar to my example image below.
Now all we have left to do is some minor optional tweaks. In my example image below I set the layer opacity of the reflection to about 25%. I also added a dropshadow by creating a very thin, feathered ellipse and placed it below the top object. You can achieve some really nice results by messing with background colors and layer opacity settings. Give it a try!