RE: Touchscreen Calibration Methods
actually I just implemented the method suggested in the article in a dsPic33 and I'm impressed at how accurate it works.
There might be simpler methods for calibrating though they would depend on certain premises as to how accurate your touch foil is mounted on the screen. So, for instance, I hold it conceivable to simplify the method if you assume that you do not have any rotation but only translation & scaling. In that case, you can simply try and sample two points (e.g. top left, bottom right) and simply interpolate x and y values.
beware of ASCII characters when posting. better safe than sorry!