I have a cooling system leak on my 07 hyundai sonata.?

Can anyone tell me the name of the part in the picture(click on this link to see the pic) a href="http://www.flickr.com/photos/38132393@N03/3507172389/" rel="nofollow"http://www.flickr.com/photos/38132393@N0…/a and If replacing the gasket here would be easy enough to do at home? BTW the cooling system is due for a flush which is how I found out about this leak. The two hoses in the pic run to and from the radiator the hose on top runs into the top of the radiator and the hose going down runs to the bottom of the radiator. And presumably the metal part that heads left out of the picture goes to the engine block I can't see though my air filter is in the way and I have misplaced my flash light.