It depends on the recipe. If it's a dessert recipe where a sweet substitution would work, you can use an equal amount of red grape juice for red wine or white grape juice for white wine. In a savory soup or stew, try replacing the wine with the same amount of low sodium chicken or beef broth, but keep in mind that even low sodium broth is going to add lots of salt flavor to your dish. You may want to reduce or omit the amount of salt you use, or add it a little at a time at the end.
If the recipe calls for just a tablespoon or two of wine, you can usually just leave it out.