Dot matrix in photoshop

Hi, I am looking for tutorial to make effect (halftone/square dot matrix) like in this page “trac.edgewall” (put that in google, click the first one) - the effect is on top right banner

does anyone know tutorial link for this effect or step how to do this?

Thank you,

Tom

Hi,

Below are some links of the tutorials.

http://www.rnel.net/tutorial/Photoshop/12530
http://www.rnel.net/tutorial/Photoshop/12455
http://www.think-designs.com/tutorials.php?subaction=showfull&id=1084338987&archive=&start_from=&ucat=3&

Hope this helps,
Cheers,