I need help identifying two engine parts.

The one on the valve cover is the PCV valve and if the one in exhaust is threaded into the exhaust manifold and has wires coming to it then yes it is the o2 sensor and if its a v-6 it will have one on the other manifold and have some in exhaust past the cats.

@enginecreator... TWO questions... 1. For the upper circle, if that is the PCV valve, based on what I searched online, it is actually the other end, not the pcv valve itself. At this link, it is what they label the "crankcase ventilation nipple". Does that sound correct? Is there a better name to search for more information on it? It was loose, and when I inspected it, the o-ring was intact, so I just pushed it back on. Now it seems fine... 2. for the lower circle, is that entire thing the exhaust manifold? It appears to be leaking oil somewhere, I need to inspect it further, because based on my research, neither the exhaust manifold or O2 sensor should be leaking oil...

Sorry, this is the link I was referring to for the PCV Valve "nipple" http://www.moparpartswebstore.com/p/Chrysler_1999_Concorde4- DR/NIPPLE-Crankcase-Vent--Make-Up- Air/42185735/04663712AC.html

The PCV can be just a vent for crank case and/or a valve that routes this back to engine to burn it up. Older and hot rods may have just a breather vent , both kep the oil from coming out with the vented gas/air mixture. The Manifold & o2 can not leak oil I suspect its the valve cover gaskets and may just need to be lightly tightened back down. And the nipple may just be the description of the part that the hose attaches to, you can undo it and pull it out if its PCV Valve and shake it back and forth to hear it operate (clicking sound) may need cleaned out also if its full of dried oil & carbon.

If it has a PCV valve it will be in the valve cover and have a vacuum line running to it as it would not work correctly it the valve was on the other end.

Ok. I will inspect it later. Based on what you have said, and that diagram, it is the PCV valve on the crankcase end, not the manifold side. It had popped off, but after I cleaned it and inspected it, the o-ring was intact, so I was able to pop it back in. I will further inspect later. Perhaps the exhaust manifold area was smoking due to oil leaked when the PCV valve had popped out. I will clean the entire area thoroughly and inspect it again. Thanks for your help!!! :)

Looking the site it is hard to say because it does not say its a Valve. But if it has one which I looked at a auto parts site and it list one for this model and it looks like this below.

That is a very possible reason for the oil on manifold.

I just wanted to followup with the outcome! So as it turns out, the PCV valve was plugged, which caused the connector at the valve cover to come off to relieve the pressure. When I reconnected the valve cover, it added pressure to the system, so then the oil started spilling out of a pinhole in the dipstick. (We think it is weird there is a hole there, but oh well). I was able to get the PCV valve for $10 at autozone, and a new connector for the valve cover at pick a part. (And while we were there I picked up a new mirror - mine has been cracked for over a year - and some hood struts, so my hood stays up on it's own! Yay!). Thank you for your help! All in all, it worked out pretty inexpensively! :)

Thats great.