I need some more information:

1. What does '/usr/sbin/lpinfo -l -v' say?
2. What does '/usr/sbin/getenforce' say?

1. /usr/sbin/lpinfo - -v    gives:
Device: uri = socket
        class = network
        info = AppSocket/HP JetDirect
        make-and-model = Unknown
        device-id = 
Device: uri = beh
        class = network
        info = Backend Error Handler
        make-and-model = Unknown
        device-id = 
Device: uri = hal
        class = direct
        info = Hal printing backend
        make-and-model = Unknown
        device-id = 
Device: uri = socket://128.135.149.16
        class = network
        info = HP Color LaserJet 3800 128.135.149.16
        make-and-model = HP Color LaserJet 3800
        device-id = MDL:HP Color LaserJet 3800;DES:HP Color LaserJet
3800;CMD:POSTSCRIPT,PCL;CLS:PRINTER;
Device: uri = socket://128.135.149.67
        class = network
        info = HP Color LaserJet 3800 128.135.149.67
        make-and-model = HP Color LaserJet 3800
        device-id = MDL:HP Color LaserJet 3800;DES:HP Color LaserJet
3800;CMD:POSTSCRIPT,PCL;CLS:PRINTER;
Device: uri = socket://128.135.149.69
        class = network
        info = HP Color LaserJet 3800 128.135.149.69
        make-and-model = HP Color LaserJet 3800
        device-id = MDL:HP Color LaserJet 3800;DES:HP Color LaserJet
3800;CMD:POSTSCRIPT,PCL;CLS:PRINTER;
Device: uri = hpfax
        class = direct
        info = HP Fax (HPLIP)
        make-and-model = Unknown
        device-id = 
Device: uri = socket://128.135.149.2
        class = network
        info = hp LaserJet 4250 128.135.149.2
        make-and-model = hp LaserJet 4250
        device-id = MDL:hp LaserJet 4250;DES:hp LaserJet
4250;CMD:POSTSCRIPT,PCL;CLS:PRINTER;
Device: uri = hp
        class = direct
        info = HP Printer (HPLIP)
        make-and-model = Unknown
        device-id = 
Device: uri = http
        class = network
        info = Internet Printing Protocol (http)
        make-and-model = Unknown
        device-id = 
Device: uri = ipp
        class = network
        info = Internet Printing Protocol (ipp)
        make-and-model = Unknown
        device-id = 
Device: uri = lpd
        class = network
        info = LPD/LPR Host or Printer
        make-and-model = Unknown
        device-id = 
Device: uri = scsi
        class = direct
        info = SCSI Printer
        make-and-model = Unknown
        device-id = 
Device: uri = serial:/dev/ttyS0?baud=115200
        class = serial
        info = Serial Port #1
        make-and-model = Unknown
        device-id = 
Device: uri = serial:/dev/ttyS1?baud=115200
        class = serial
        info = Serial Port #2
        make-and-model = Unknown
        device-id = 
Device: uri = smb
        class = network
        info = Windows Printer via SAMBA
        make-and-model = Unknown
        device-id = 

2: /usr/sbin/getenforce     gives:
Disabled

What does 'ls -l /dev/lp0' say?

ls -l /dev/lp0 gives:

crw-rw---- 1 root tty 6, 0 2008-03-07 10:01 /dev/lp0

Should be group lp.

What does 'rpm -q udev' say, and what does 'rpm -V udev' say?

rpm -q udev gives:    udev-118-1.fc8
rpm -V udev gives nothing

What about 'rpm -q pam' and 'rpm -V pam'?

rpm -q pam   gives:
pam-0.99.8.1-17.1.fc8

rpm -V pam   gives:
....L... c /etc/pam.d/system-auth
S.5....T c /etc/security/limits.conf

Do you know why /dev/lp0 is group tty and not group lp?

Anyway, not a system-config-printer or cups issue.

$ fgrep -r lp /etc/udev/rules.d/
/etc/udev/rules.d/50-udev-default.rules:KERNEL=="parport[0-9]*",        GROUP="lp"
/etc/udev/rules.d/50-udev-default.rules:SUBSYSTEM=="printer",          
KERNEL=="lp*", GROUP="lp"
/etc/udev/rules.d/50-udev-default.rules:SUBSYSTEM=="usb",              
KERNEL=="lp*", NAME="usb/%k", SYMLINK+="usb%k", GROUP="lp"
/etc/udev/rules.d/50-udev-default.rules:KERNEL=="lp[0-9]*",            
GROUP="lp", SYMLINK+="par%n"
/etc/udev/rules.d/50-udev-default.rules:KERNEL=="irlpt[0-9]*",          GROUP="lp"

not udev's fault.. makedev seems ok, too...
$ fgrep -r lp /etc/makedev.d/
/etc/makedev.d/01generic:a generic lp
/etc/makedev.d/00macros:=PRINTER  660 root lp
/etc/makedev.d/01linux-2.6.x:c $PRINTER               6   0  1   4 lp%d

Hmm, after upgrading a box from FC5 to F8, I had a weird breakage of the
cups->parallel port printing.  I just tried a zillion things and what worked was
a wild shot in the dark: chmod 666 /dev/lp0.

Mine was 660 root:lp before.  Not sure why 6 on lp isn't good enough.  Any ideas
what I should check?

Thanks for the info.  I tried doing a chmod 666 /dev/lp0 and had to put it into
/etc/rc.local since reboots reset it.  Also, I did a chgrp lp /dev/lp0 which
doesn't reset on reboots.  Now I can finally print to my local printer.

Udev is responsible for setting up this port, I think.  I have no idea why yours
is setting group tty.  Do you have any custom udev rules in /etc/udev/*?  I'm
thinking you must.  Maybe grep -ir tty /etc/udev.  Once you are 666, it doesn't
matter what the group is anymore.

Also strange is that my own personal box has a parallel printer and it is
working fine under 2.6.24.3-12.fc8, udev-118-1.fc8.  I haven't rebooted into -34
or -50 yet.  And those are probably what you are using, based on the date of
your original post.  Perhaps -34/-50 introduced the bug?  I'll see when I reboot
next (not easy on my personal workstation).

Hopefully someone with knowledge of udev/kernel can elaborate.

If you have the ability, maybe reboot into kernel-2.6.24.3-12.fc8 or earlier and
see if the problem disappears (after commenting out your rc.local change first).
Just glancing at my (working, old kernel) /dev/lp0 shows that it's 660 root:lp.

probably seem kernel USB config option changed. someone care to compare?

I have no custom udev rules.  I'm simply doing a full install followed by
applying  all of the latest patches.

On a related note, I just finished a new install using the 2.6.24.3-50.fc8 kernel.
The USB printer was not showing up in system-config-printer until I changed the
group ownership of /dev/usb/lp0 from tty to lp.

It is not a udev bug... udev sets group lp not tty.. so please reassign this bug
to the component which sets group tty ..

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