Create new file with 130 X 75 pixels, 72 PPI and white background. (It is just for tutorial. Real web button will be much smaller then this. But the procedure will remain same.)

Select Ellipse Marquee tool. Drag it on the file. Create new layer and fill the selection on the new layer with black. Name the layer as base.

Open the desired texture file. Select Move tool. Drag the image on the button file and adjust so that black ellipse will get properly covered with texture. In the layer palette you will get texture layer. Keep this layer selected.
Layer > Group with Previous (Ctrl+G)
Select base layer

     

Layer > Layer Style > Bevel & Emboss + Drop Shadow

In the place of texture you can take any picture to make the buttons which will perfectly suitable for the theme of your web.