look at the brushes section as it is in somebody's brushpack or go to deviantart and search for it , somebody who has it may post it for you here
yeh i dont like them, the grunge brushes I use are named like this >> r06_grunge, what ever they are.
i use hellzent and stale mate along with terrorist grunge, those are three really good sets, I have gotten to the point where if i goo good enough i can make a background in around 2 or 3 minutes and have it be decent