Plastic buttons are great for using on web site interfaces, so now you are going to learn a very simple way of creating a nice looking button!
Step 1: Create a new 100x100 document with a transparent background.
Step 2: Set your foreground color to black, and then select your rounded rectangle tool. Set the radius to 20 pixels. Now click the options arrow and choose fixed size. Set the width to 140 and the height to 30. Now create your rounded rectangle.
Step 3: Click the layer styles button (button with an 'f' in a circle) and choose gradient overlay. Use the following settings:
Step 4: Still in the layer styles menu, choose outer glow and apply these settings: (Do not press OK after you're done)
Step 5: Now go to inner glow and apply these settings:
Step 6: Click OK once you have applied the inner glow settings, and now your finished! If you want you can take it a step further by applying a white-transparent gradient to give it a reflective effect. See the Glass Sphere tutorial for more details on how to do this. Here's the final product (with no reflection):
