I'm not familiar with Ubuntu. However, for Slackware the devices are
now automatically mounted with Udev, HAL, D-Bus, and autofs (afaik).
To have devices such as USB flash disks automount, we simply add our
normal users to the cdrom and plugdev groups in /etc/group. You can
do this by opening a terminal and then "su" to root, then issue "vigr"
and add your normal user to those groups, and any others you think
may be necessary. After saving the changes to the file it is necessary
to restart D-Bus by issuing "/etc/rc.d/rc.messagebus reload".
If this is the method that works with Ubuntu, there is no need for an
entry in /etc/fstab for USB flash devices.
Have you searched the Ubuntu forum here at LQ, <Linux> Google, and the
Ubuntu Wiki for help with this problem?