Custom PHP Page

Hi there.

Just a quick question.

Ive got a php page that i use to show some custom work.

I use the WP header, sidebar and footer with the page so it all looks the same its just accessed from /page.php

I want to be able to use the wordpress login / user system so people can interact with the page.

Is there a way to use this ? I know wordpress doesnt use sessions.

Id like to be able to detect between an admin account and a normal account if possible.

Anyone got any tips ?

Thanks, Sam!