Here is an easy way to make cool interface buttons with gradients.

The first thing you'll need to do is open up a new file and make it any size you like, I made mine 200x200. Then make a rectangle in the middle of your image, and then right click on the paint-bucket in your tools menu to select gradient

Now make sure your gradient is set to linear, and make your background and foreground colors to dark gray and light gray. Now use the gradient tool and fill it so that the light part is on the top and the dark part on the bottom.

Now go to select>modify> contract, and contract by about 5, depending on the size of your button.

Now fill it with a gradient with the opposite directions, so that the light is on the bottom., and the dark on the top. Then go to stroke and stroke it with a dark gray, with 1 px.

Now that you have your basic button, you can either leave it the color that it is, or change the color using my 'color change" tutorial.

Then just add text, and you are just about done.

Now I just adjusted the size to a lot smaller and added a few more buttons.