TheRecipeManager provides a comprehensive list of ingredient substitutions. If you have ever needed self-raising flour but run out, then this can be very useful.
You can view the substitutions, by selecting 'Kitchen Helpers' from the 'View' menu, or by pressing the 'Ctrl' + 'k' keys. This opens up the Kitchen Helpers window. From there select the 'Substitutions' tab.
You can add, modify or remove any of the substitutions.