Is there something like is_admin() / is_loged_in()

[shawn_a]

I think 3.1 has sitewide cookies by default, so you should be able to just read the cookie, or use globals.

Code:

GLOBAL $USR;

if (isset($USR) && $USR == get_cookie('GS_ADMIN_USERNAME')) {
  // do stuff
}

Might not be entirely accurate, I only briefly looked into it, I want a working edit this page plugin.