Designing a cutting edge letterhead

Create a thin rectangle using rectangular shape tool.

Press Ctrl+J and Ctrl+T. Move a few pixels down. Now keep pressing Ctrl+J and Ctrl+Shift+T several times to create the design as shown. Select each layer and change it's color.

Using pen tool create a shape as shown below. Move this layer below all the layers in layer order in layer palette.

Except the top two rectangles select and merge all the colored rectangle layers. Press Ctrl+Alt+G to create a clipping mask.
Create a rectangle at the top using rectangular shape tool.
Create a few multicolor irregular rectangles over this rectangle. Select and merge these layers.

From "Filter" menu select "Blur>>Motion Blur ". Apply settings as shown.
Change the layer mode to "Color Burn". Press Ctrl+Alt+G to create a clipping mask.
Duplicate layer. Rotate a bit and change layer mode to luminosity.
Insert company logo and contact details to finish the letterhead design.