First you need an brick wall as a background. You can search the image on the Internet.
Open a new file having 1024×768 px and 72 dpi.
You may use a brick wall as a background for the picture.
Press on Shift button and make use of the next instrument 
to represent a lot of circles colored in 5D4D4D.
Now select the shape in overlay mode.
Insert the same way a lot of other circles, colored this time in 606060.
Set Overlay on the shape too.
Using the same instrument applied before. represent one more layer of circles colored in 568F8F.
Fill 70% on the layers and set Overlay option for them.
Write now the site’s name
Set this time Hard Light on the layers.
Blending Options-Drop Shadow
Select a brush with blurred edges on a new layer and try to draw several patches on the picture. They should have different colors – 5C0003 and 160F2B.
Set Overlay on the layers.
Draw on a new layer several yellow patches and select the option Filter Liquify to make everything look like in the picture (the colors should be blurred out with SmudgeTools(R) and unnecessary elements may be erased with the usual instrument.
And the grand finale
Graffiti Alphabet 