A website full of tutorials around eTextile from the duo Kobakant.
A hackerspace in Paris specialised in Textile, nice and detailed material category (in french).
CONDUCTIVITY / RESISTIVITY
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is an intrinsic property that quantifies how strongly a given material opposes the flow of electric current. [ref]
Certain fabrics can be piezoresistive and use to make sensor like pressure. The piezoresistive effect is a change in the electrical resistivity of a semiconductor or metal when mechanical strain is applied
USE A MULTIMETER
MAKE A SIMPLE CIRCUIT
MAKE A SWITCH
———— Regular fabric ————
Three Fabric Buttons by Plusea
Tutorial on Instructables
MAKE A PRESSURE SENSOR
Material : conductive thread, fabric, velostat, 10k ohm resistance, thread
Tutorial for Conductive Thread Pressure Sensor on Instructables