Plugin interface design?

FROM : Adam Knight
DATE : Fri Aug 04 17:25:22 2006

So, a general question...

I've read about how to make plugins, and I've written a demo app that 
finds and calls a method on the plugin.  That much I have.  However, 
what I can't seem to locate out there is a good document about how to 
design a plugin interface for various problems.  That is, if I want 
to hand processing off to a plugin, or have it extend the GUI in one 
place, etc. as to what concepts could be employed in the protocol to 
make that easiest.

It's theory, and not proper for a discussion here, but if anyone has 
some links or resources to follow up with, I'd love to see it.

Thanks!
--
Adam Knight
codepoetry - http://www.codepoetry.net/products/