Photoshop Plug-ins to Illustrator?

I know there's a thread on this somewhere; I asked the question, but I can't find hide nor hair of it..

the question is: how to get photoshop plug-ins available to Illustrator.

my recollection is that a folder is copied (first made visible?) from within the PS folder, and dragged to a spot in the Illustrator folder, but I can't seem to recreate the steps.

Thanks for any clues about this!

w