How to create rows/columns of dots?

I have to create this banner and in the banner i want to have dots, but not just random dots - they must be equally spaced vertically and horizontally. More or less like a grid being placed - but everywhere the lines (horizontal/vertical) meet - there is a dot and the rest of the lines cannot be seen.

any easy way of doing this? can I control dot size?

thanks for any help!

First thing that comes to mind is simply making a photoshop document 20 x 20 putting getting a 10 pixel brush for the pencil tool and putting a single dot in the center of the document. then CTR+A to select all and then go to >Edit >define pattern

Now you can fill anything with a dot by going >Edit >Fill and selecting "pattern" and then choosing the pattern you created....(adjust the document and dot size as you wish... just define another pattern)

Second thing that comes to mind is to set the spacing to 200% or 250% and just holding shift as you paint a line...

did the first method, worked great - thanks tornupinside!!