Depending on what the label says, either dry clean or wash with soap to maintain your coat's waterproof qualities. Do not use detergent. But remember that soap flakes should not be used in a front-loading machine. If you have this type of machine you should wash the item by hand.
For Gore-Tex branded clothes any detergent can be used. Remember to wash the clothes on a gentle cycle. Do not use a fabric conditioner. Gore-Tex garments are treated with Teflon, which makes them water repellent and a fabric conditioner can remove the Teflon, affecting the performance of the garment. It would still be waterproof, so water would not reach your skin, but the garment itself could become heavy and water-logged. For more information, Freephone Gore-Tex on 1800 226 703 or visit their website http://www.gore-tex.com/