Starting 2008-02-20, there are drivers for 3M touchscreens, like the one implemented in the Planar PM191U 19" monitor.
These drivers are binary-only and only for 32bit machines. 3M did not respond so far regarding a 64bit version.
To install the drivers, run this:
apt-get install 3m-touchware
and reboot the machine.
To calibrate the screen, run /TWCalib/TwCalib inside X.