LDN - Luminis Developer Network

Ok, I'm breaking down and asking...
I can't figure out how to change skins manually outside of the deployskintemplate command and admin screens. I want to do this with a PHP page, or Perl script or something.

I can do this with Luminis III.x but can't figure it out for IV.x

I know its possible, I saw a demo by Plymouth State (I think it was) at Summit, and they had a skin chooser app, it rocked.

Anyway - any hints ?
-Jon