you can try with a dots brush in photoshop. make the dots make a text and paste it as mask on top of the dots. here is an example but i'm sure you can find more like this brusheezy.com/brush/495-Dot-Round-Brush-Shape hope it helps
Open new file. Add a new layer and select black text and add an 'a'. Select new layer and use white colour and a halftone brush to add white dots. At layer setting add a clipping mask. Select blue colour and infill a particular dot. I have used a 1pt black stroke to separate the edge of the 'a'. If you need a set of half tone brushes then PM me. Regards, LTL
The pattern is more varied on the design he wants It is a very simple to create the design PM me if you want to add me to msn and i will tell you step by step on how to produce it. See my thread: http://forums.digitalpoint.com/showthread.php?t=1269819 for contact details Cheers
its pretty easy, and can be done through, PS brushes, Dots or circles. All you have to do is to just play around with their sizes and Alt+Select Drag to duplicate them and arrange them as you want them to be.
you can use brush for dots, or you can creat 1 dot and then you can copy paste for logo, ithink corel is great