You should find cookbooks tailored to your allergies. Substitution methods vary widely depending on what kinds of recipes you're making and what types of ingredients you're replacing.
You have many options depending on you allergies, ie using soy milk instead of cow, etc. Try a natural food store for advice and perhaps some book titles.
The internet is a fabulous tool for finding out almost anything you want to know, including substitutions for allergies. Just google the questions and lots of answers will pop up.
