Hi,
The touch screen I have shown and used is what EA call a Digital Resistive type, which has a 5x3 switch matrix.
This type does not have or need a controller of any sort, you just connect it to your micros input port with a pullup resistor like any conventional switch.
You can connect it as a full 5x3 switch matrix, but I do not need so many, in my test picture, I just use three of the bottom row connected to the micro with the bottom common rail to 0v. (my screen graphics switch boxes are really too big - it was just an image I had to hand for my first test )
You can measure the 'switch' resistance with a meter , its about 1k on and over 20meg off. - you could easily use it on things other than the glcds.
The price in here is GB £8.50 plus taxes etc. + the little cable connector which is a must.
There is another type of screen usually refered to as an Analogue Resistive, that does require a separate controller and allows you do much more, like direct touch entry graphics etc.
hth
Richard