Can I substitute Soy Milk when a recipe for baking calls for regular milk?

The short answer is yes; the longer answer depends on what kind of soy milk you're buying and how you plan to use it. I've used soy milk in my breads and cakes without noticing much of a difference in texture, but I use the unflavored, unsweetened versions of it (especially in cake-baking, as many recipes call for vanilla and some soy milks have vanilla in them). I avoid "light" soy milk when making creamy dishes or sauces because I want them to have the creamiest texture possible. If you're using soy milk in a soup or stew, don't allow it to boil because that can cause the "milk" to curdle (and add your acids at the end of cooking, also to avoid curdling). Oh, and be aware that some brands of soy milk are very sweet (you can buy it unsweetened, though); the sweetness might not work well in some dishes.

Yes, you can substitute soy milk powder if it's not for any dietary purposes or yours not allergic to anything full cream powdered milk can b used. There's also other milk almond. Not sure if that's in powder form.