Result:
Click here to view!

1. First start a new canvas, doesn't matter about the size, I'm going to use 640*480 for this tutorial. And start up with a transparent background. Begin with a new layer and make a circle using the elliptical marquee tool (m) and fill it with white, this will be the body of the snowman, so it should be big. This is how mine looks:
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2. Next, double click on the snowman body layer to bring up the layer style window, and go to Bevel and Emboss. use the following settings and click ok.
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3. Now we are going to create the head of the snowman, so make a new layer and using the elliptical marquee tool (m) make a circle on top of the body and fill it with white.
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4. Now bring up the Layer Style menu and use the following settings and click ok:
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5. Now we are going to work on the head and then down to the body, so make a new layer and lets start making the eyes of the snowman. Using the elliptical marquee tool (m) make a small circle and fill it with black like the following screen shot:
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6. a) Next, using the elliptical marquee tool (m) make a smaller circle overlaying the last circle you made and fill it with white. now merge this with the last layer you made by holding ctrl+E and duplicate it to make another eye, and then move the duplicated layer across from the original layer and align it with the head so it doesn't look out of place.
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b) Now merge this with the last layer you made by holding ctrl+E and duplicate it to make another eye, and then move the duplicated layer across from the original layer and align it with the head so it doesn't look out of place.
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7. Once your done the last procedure, continue on to making the nose with a new layer and using the elliptical marquee tool (m) and making a small circle (not too small a bit bigger than the eyes) and fill it with white. Then double click on the layer to bring up the Layer Style window, and go to bevel and emboss and put the following settings in:
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8. Now go to Color Overlay and punch in the following settings in and after that click ok:
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9. Now we are going to make the smile, so make a new layer and using the rectangular marquee tool (m) make a small rectangle like this and fill it with black:
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10. Now duplicate the layer 4 times (depending on how big you want your smile you could duplicate it more) and arrange them like the following screen shot:
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11. We are done with the head, lets move on to adding details to the body. So make a new layer and get your Polygonal lasso Tool (L) and create a selection somewhat similar to this, make it look like its wood or a stick found of a ground, once your are done making your selection fill it with the following color #523407.
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12. Next make your other hand, the same method and technique as how you made your other hand and fill it with #523407.
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13. Make a new layer under your hand layers and get your brush tool and get a 'Soft Mechanical 16 Pixel' brush, and just do a light one click brush under the tip of the hand that is coming out of the body. Do this for both hands/sticks and lower the opacity to 25-30%.
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14. We are almost done!! We just need to finish up the buttons on the body. So make a new layer, make sure its on top of the body layer and get your rectangular marquee tool (m)
and make a small rectangular similar to the following image:
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15. Now just duplicate that button layer three times and arrange it to look like normal buttons.
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This concludes our tutorial, you should have something similar to this:
Click here to view!