We are going to create a sunburst pattern, and then  clip a  paper to it. I will also show you how to apply a slight twirl to it as well. 

You will start by creating a blank canvas, I am working on 12x12. Use your shape tool to create a long rectangle down the entire lenth of the page. it can go past the end because we will be cropping it later to ensure  all rectangles are equal size. Now duplicate this layer, and slide it over a bit on your canvas. You will do this accross the entire canvas as  shown in these images

After you have your canvas covered with long rectangles, you need to evenly space them. if you look at the top of the toolbar, where the little box from my mouseover shows "align vertical layers" you can use this to evenly space the items across your canvas.after evenly spreading them out using this tool, go ahead and merge your rectangles into one layer. Select the blank layer below your rectangles, and select all of the layer, then crop it so that you crop any overhang from the rectangles off of your image.

Now depending on how wide you made your rectangles is going to determine the width of each ray of your sunburst. Keep this in mind for playing for different sizes later on.

Go to filter>distort> polar coordinates  and make sure you have it on "rectangular to polar" and hit ok! Easy enough right? now you have a fantastic sunburst pattern that you can save as a pattern, use as a shape, whatever you want.

If you wanted to add a little more to your sunburst, you could twirl it to get a bit of a wave to each ray. Go to filter>distort>twirl and  put a *very small* ( i used  25 or so in this example ) twirl on it and  it will twist just slightly.

Lets thinking on how this might be usefull for a layout. For this example we are going to clip a paper to it, and put a paper under it, as we might do if we were creating a layout. Slide your background paper behind the sunburst. and another paper on top of the sunburst. Then you will want to ( in PS, i dont know the shortcut in other programs )  control Click on the  sunburst layer in order to select the sunburst itself. right click on the paper layer name and ( with the paper layer selected ) chose " create clipping mask "

And there you have it, the start to a really fun layout with your very own sunburst that you created! I hope you enjoyed this tutorial and have fun trying it out!