I have only installed phpMyAdmin once.. does it do the following..

Can i install it globally so its first page is a login screen, the user puts in there database,user,pass and it connects them to that database to modify.. or do i have to install a user specific version everytime someone wants ot use phpmyadmin..

Is there any other MySQL management scripts (free) which i can simply install once and give all my hosting customers with databases access to ?