this tutorial only works if you have Photoshop Elements.
example: 
1. first open up a new image. then Find the Rectangular Marquee
Tool (or as i like to call it the select tool) 
and
select a small portion of your image on the right side. make sure its from
top to bottom, like so: 
try
to make the width small.
2. now, press shift and your cursur should turn into something like a big
+ sign next to a smaller one. this allows you to select more than one thing.
so while you are pressing shift, start to do the same thing as in step 1
on the top of your image. let go of shift before you finish. make sure the
selections width is again only a little bit. and also make sure the selection
goes all the way from right to left. continue to do so untill the entire
border is selected. the edges should look like this 
3. Now that the border is all selected, go to filter>>other>>dither box...
a new window should pop up looking somewhat like so: 
depending
how big you want your dashes to be, you can set the dimentions to 2x2, 4x4,
6x6, or 8x8. i used 4x4 for this image.
4. now color in the boxes so that they look like a checkers board using
any two colors you think look good together. once you are satisfied, click
fill. 
your border
should be filled in now. thats it!
having problems? tutorial didnt work? dont know what something is? Email me and ill see if i can help you!