basically I've developed my own PHP News system which has an admin backend attached to the website with a user login area. I have also put on Plogger to the same website to control the main image gallery.
What I would like to do is have one login which allows you to access both my system (controlled through cookies) and plogger, so if you wanted to add a news story and a new image gallery, you wouldn't have to login to two different login screens.
The easiest way would be to use my main admin login screen (once you've logged in has a link to the plogger admin), but once you've logged in through my screen it bypasses the plogger login and goes straight to the admin panel.