how can I do this effect?(reui sign)

http://img715.imageshack.us/img715/3312/jimbei2how.png

(reui sign)

You need to get Topaz denoise. It's a plug in filter for CS you can download a month free trial.

http://www.topazlabs.com/denoise/

you can also use topaz clean 3

Clean 3 is the one for that though