Sorry I didn't do a
guide, but did have a couple of photos of my intercooler when I removed it. Can't remember where they are now though !
IMO oil down there is all pretty normal and not really worth worrying about....
EDIT: As Nic (Cheshire Cat) said, what would be more worthwhile is to clean all the flies/leaves/stones etc out of the intercooler fins, to get as much airflow over it as possible. Easier to do when it's off the car - best way is to hose it through from the rear side to flush all the crap out of the front.