how do I compile/install a plugin?

I'm having some trouble just trying to figure out how to do a simple 
compile and install of a ethereal dissector plugin.  I am using OS X on 
intel.  I downloaded the source code for 0.99.0 and I see that there is 
a plugins directory in the source tree.  If I run ./configure and then 
make in the plugins directory I get some *.la files.  Then I tried 
copying one of the *.la files into the plugins directory of my darwin 
ports install of ethereal (i.e. /opt/local/lib/ethereal/plugins/0.99.0/)

I can't seem to get anything to work.  I tried modifying the source code 
of one of the plugins to use a different tcp port just to see if it is 
working, but it didn't seem to do anything.  Is there a way to tell if 
the plugin has loaded or not?  Do I need a *.so file?  All of the other 
plugins in that directory have *.la and *.so, but when I compile I only 
get a *.la file.  Sorry for my ignorance.  I'm kind of in a time crunch 
and I don't see much documentation on this.  Any help would be appreciated.

-Nathan