I am looking for a tutorial on how to set up a movieClip loader to load external swfs.... example, on mouse click of a button a new swf file would load in a movieClip loader.

The best example would be the help files under MovieClipLoader. The code there
shows exactly how to use it and everything you need to know.

I do seem to recall that there are a lot of trace statements. Those made it
difficult for me when I was first learning it so just delete them if you like.
Also the sample code under MovieClipLoader.loadClip() has two implementations.
You only need one of them to understand how it works.