Create a New document and select the rectangle tool. Draw a rectangle, 80 pixels of width and 40 pixels of height. Set the rectangle roundness to 30.

STEP TWO
We have to set background for the rectangle. Select Gradient -> Linear and set colors like they are marked on the image below. Also, place the background line like it’s shown on the image below.

STEP THREE
Now, set background to 1, 1-pixel Soft style, with #666666 color.

STEP FOUR
Select the rectangle tool and draw a rectangle, 1 pixel of width and 40 pixels of height. Set backgound to Gradient -> Linear and set the colors that are marked on the image below. Place the background line like it’s placed on the image below. Image is zoomed 400%.

STEP FIVE
Copy the second, 1 pixel wide rectangle, and select the first one. After you selected the first small rectangle, go to Modify -> Transform -> Numeric Transform and select Rotate option. Set rotation angle to 55. Now, select the second small, 1 pixel wide rectangle, and go to Modify -> Transform -> Numeric Transform and select Rotate option. Here you must set rotation angle to 305.
(zoomed 400%)
STEP SIX
Place each of the two small rectangles, like I placed them on the picture below, over the first, big, rectangle. Image is zoomed 400%.

STEP SEVEN
Select the Ellipse tool and draw a small ellipse, 8 pixels of width and 8 pixels of height. Set it’s background to #E66F02. In the Properties window go to Effects -> Bevel and Emboss -> Inset Emboss and set values like they’re shown on the image below.

STEP EIGHT
Now, place the small ellipse over the first biggest rectangle, like it’s shown on the image below. Image is zoomed 400%.

The step above was the final step. That’s all and the mail icon is done. Below are my mail icons.

Used software: Fireworks MX 2004