What is a substitute for red or white wine in a recipe?
For white wine, try:


chicken broth/stock
vegetable stock
white grape juice
ginger ale
canned mushroom liquid
diluted white wine or cider vinegar


For red wine, try:


beef or chicken broth/stock
diluted red wine vinegar
red grape juice
tomato juice
canned mushroom liquid


A great list of substitutions for cooking with various alcoholic ingredients may be found here.