For this tutorial I will teach you how to do a web like effect great for signatures or wallpapers

Step 1.
Open up a new document of 500x500. and make sure is transparent 

Step 2.
Now pick the foreground colour as red and then pick the Gradient tool and use the following settings


Step 3.
Now make a fare amount not to much though of gradients then go to the foreground and make the H on the panel go up 50 and repeat to you reach 300 (very the thickness for a better effect)

Step 4.
Now go to Invert (Image>Adjustment>Invert). and the desaturate the image by clicking CTRL+SHIFT+U and then to go plastic wrap and use this settings:


Step 5.
Now make a new layer (Layer>New>Layer) and fill it with white. now put that layer behind the the web layer and fill your now background white layer with scan lines (Click here for scan line tutorial) and the press CTRL+U and pick the colour you want for your design and your done.