Just your ordinary plastic button... but easier
1. Make a new image, ours is 180 x 85 - with a white background
2. Fill the background with a soft blue [ we used #3A6795]
3. Make a new layer + click your rectangular marquee tool and click Style > Fixed size - and give it a fixed size of 150 x 45 px
4. Click your screen to make the rectangle
5. On the layers palate, click Channels, and click create new channel
6. Fill the rectangle in with white by hitting ALT + Backspace
7. With it still selected, press Filter > blur > Guassian blur - and give it a setting of 12
8. Click Image > adjust > levels and give it these settings to smoothen the ovalar shape
9. Click ok
10. Hold CTRL and press D to deselect
11. Hold CTRL and click the thumbnail of the alpha layer on the channels palette
12. Switch back to your layers palate, and CLICK THE TOP LAYER and fill the selection with any colour.
13. Click Layer > layer style > blending options and give it all of these following settings...
that's all there is to do it... it takes a bit to get all the settings right, but not as long as it took me to make this thing
If you click NEW STYLE on the blending options, and give some text that style, it looks pretty cool also

