Administrators post in different colors
 

I've tried searching for every combination of words I can think of to see if there's a mod or some information about this, if it's possible.

On the world of warcraft forums (and in the pw-wow mod) you can flag certain usergroups to have their post and their postbit in a different color than other users. I'm trying to do this for my website, but I am not well enough versed in php or vBulletin modification to risk toying with code.

Is there a mod out there or some information I can read that does this already?

I created a modification long time ago that allowed specific usergroups to change the background for a post. See my profile, maybe you can use this one.