1) Open a new 20 0X 300px file.

2) Select the rectangular marquee tool and make a rectangle. Fill the selection with desired color.

3) Apply Bevel and emboss. Adjust the structure and shading.

4) Now make a selection as wide as you want your groove and 2 pixels high.

5)Then go to Image >adjust>levels. In the middle input level box type 2.0, click OK.

6) Now use the arrow keys to nudge your selection up one pixel. Go to Image > adjust>levels again and this time put 0.4 in the middle input box. Click OK.

7) Repeat this if for however many grooves you want.