You probably don't want to give them root access because then it defeats the purpose of not logging in as root 🙂
Just get into a console and type 'su' to become root and install the packages and when you are finished, type 'exit' to return back to your regular user status.
Also, I'm not sure how Mandrake handles this but you can have a group called 'wheel' that gives a user many of the same privileges as root (it can't do rm -rf / , but hey 😉 ) without having to login as root to do certain things.
-silver