Gnome SuperUser is a gtk frontend to su and as such an easy way to run a program as root in the Gnome environment. It is based on xsu by Philip Van Hoof and is now maintained by Mark Finlay.
Note from Philip Van Hoof: As Mark Finlay passed away on January 9 2004, I am again maintainer of this little project. I am not planning any major changes in a near future but I am willing to again transfer the maintainer status to people with such plans.
I would like to thank Mark Finlay for his work on Gnome SuperUser. May he rest in peace.