Thanks Marti, Lodec, chalwhen, Elvestad.
Thanks Space for the link to the font. I've changed the text and made a new version:
Compare to the original:
Large
chalwhen, I used a brush at different sizes and opacities on a new layer to create the particles, and then I changed that layer to overlay and changed the opacity of the layer. I also played around with some very slight gausian blur for the particles. I don't know if its the right way or not. I've never read any tutorials about it.