I have had a few people ask me specifically about soy milk, so thought I would do a quick post on what I use.
When buying soy milk for baking, it is important to buy the unsweetened one. This does not have any sugar in it, unlike most soy milks, which are extremely loaded with sugar (yes, even the ones marked "natrual" or "light". If you are using a normal soy milk, the sugar content will effect your baking.
You REALLY have to read the labels when buying soy milk, not just the name!
Here is what I use (am posting from the .co.uk site so it is in English, will post German site below that)