The screen needs drivers installed for it to work I think it comes with linux drivers but I am not sure I would ask the place you are buying from to look on the drivers CD to make sure before you buy it just in case my memory is bad.
I do own one.
It is a serial port connection to the PC for the touchscreen.
It needs to have the drivers installed to make it work.
I can only tell you how the windows drivers work since that is what I am currently using. Moving your finger on the screen is like moving your mouse and tapping(or putting your finger ther and holding) it works as the left mouse button but it has a little program that run in the system tray that can switch it between left mouse and right mousebuttons for the tap.
I am currently at work and do not have my drivers CD with me but IIRC it did have a linux directory on it.
ohh and here you go rammic something for your head
Yes it has a directory for linux drivers with some files in it I am not exactly sure what all is in there (looks like a shell script and a few other things) but if you want to PM me your e-mail address I can send the drivers to you (about 165K zipped) so you can look at them a little more before you buy a screen.