Don't require root to add printers

Have a look at the files in /etc/cups

I do not have a Fedora 15 system to hand - but looking at a recent RHEL box, the relevant bits are in /etc/cups/cupsd.conf

....
# Administrator user group...
SystemGroup sys root
....
# Restrict access to configuration files...
<Location /admin/conf>
  AuthType Basic
  Require user @SYSTEM
  Order allow,deny
  Allow localhost
</Location>
....
 # All administration operations require an adminstrator to authenticate...
<Limit Pause-Printer Resume-Printer Set-Printer-Attributes Enable-Printer 
     Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs 
     Release-Held-New-Jobs Deactivate-Printer Activate-Printer 
     Restart-Printer Shutdown-Printer Startup-Printer Promote-Job 
     Schedule-Job-After CUPS-Add-Printer CUPS-Delete-Printer 
     CUPS-Add-Class CUPS-Delete-Class CUPS-Accept-Jobs 
     CUPS-Reject-Jobs CUPS-Set-Default>
  AuthType Basic
  Require user @SYSTEM
  Order deny,allow
</Limit>

IIRC, @SYSTEM is a macro for the groups listed in SystemGroup