Photoshop Layers Tip ...Levels adjustment on one layer

After trying to change the levels adjustment on only one layer PS-CS3,
I found this answer in Yahoo Answers.........

When you add the levels adjustment to the layer it will create a new layer called "Levels "1.

In the layers window, drag the layer "Level 1" so it is directly above the layer you want it to affect.

Now, hold down the alt key and position your cursor right between the two layers in the layer window.

Your cursor should turn into what looks like 2 overlapping Circles. Click once. This will apply the levels adjustment only to that layer and won't affect your other layers.

I hope this information helps someone...Bill