[s-cars] Loud rattling HELP!

[JR]

I started my car this morning to a loud rattling noise coming from the 
front of the engine from the moment I started it.  Conditions outside 
where that it had rained heavily last night and it was probably about 50 
degrees out this morning.  I put my ear on the intake manifold and the 
valve cover it doesn't sound like it's coming from in either of those 
places.  I didn't have time to analyze it further, but it sounds like it 
is coming either from under the plastic injector cover or maybe down by 
the power steering pump.  I can't make up my mind whether it sounds like 
a metallic ball bearings rattling around in a can sound or if it sounds 
like normal engine sound escaping from an exhaust or vacuum leak or 
something.  It's random sounding like popcorn popping, not at all like 
the ticking of a clock.  I drove the car to work (3 minute drive) and it 
drove perfectly.  No problems, but the rattle was still there when I got 
to work.  It sounds horrible but it isn't affecting the way the car 
drives.  Any ideas where I should look?

JR