ivman is a generic handler for HAL events. Originally for automounting,
it can now be used to run arbitrary commands when events or conditions
occur or properties are modified on your hardware (e.g., run a command
when you close your laptop's lid, run a command when a particular
device is attached or a particular CD is inserted, etc).

ivman allows you to have automount feature even if you don't use a volume 
manager like KDE, GNOME, or XFCE includes. Just run ivman in the background, 
and if you're not root, be sure to also install pmount, which allows you to 
mount without being root and having the devices listed on /etc/fstab.

NOTE FROM SUBMITTER:
I've discovered a bug (possibly known) in ivman with pumount usage; since 
ivman doesn't have maintainer right now and I don't know where to report it, 
I'll explain here how to easily solve it.  Note that this happens when using 
pumount as non-root; I haven't tried using ivman as root.
It seems that when you remove a USB device without pumounting it (which ivman 
should take care of), ivman locks the device when calling pumount.  This can
be easily fixed by correcting your ivman's config files.
Set in ~/.ivman/IvmConfigBase.xml:
<ivm:Option name="mountcommand" value="pmount-hal '$hal.info.udi$'" />
<ivm:Option name="umountcommand" value="pumount -l '$hal.block.device$'" />