available starting with: LinuxMCE 0710 beta 4.
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.
The serial pnp detection scripts sometime interfere with the touchscreen and make it stuck shortly after the devices are launched. Until the detection is fixed you can edit "/usr/pluto/bin/ListAvailableSerialPorts.sh" to _not_ spit out the device file where the 3m is connected.