There are a number of ways to communicate with a touchscreen from an Arduino. Here we will review SPI vs parallel connections, and the benefits of each method.
Arduino TFT LCD Touch Screen Tutorial
Adafruit 2.8 and 3.2 Color TFT Touchscreen Breakout v2
How to Use a Touchscreen with an Arduino
Arduino Controlled Touchscreen Light Switch
Touchscreen Arduino Library for XPT2046 Touch Controller Chip
Touch screen examples: keypad, paint, image viewer and calculator - vanslooten.com
BluBerriSix - a TFT TouchScreen / Arduino Tutorial : 13 Steps (with Pictures) - Instructables
Arduino 3.2 TFT Touchscreen Mega mirrored/reversed - Car LCD gauge project - Displays - Arduino Forum
How to Use a Touchscreen with an Arduino