Instructions
Look for contact information on the packaging of the action figure itself. In this day and age, you'd be hard-pressed to find a product that did not have a web address printed on it.
Scan the website for traditional contact methods if email doesn't happen to be your thing. It is very likely that there will be phone numbers and snail mail addresses.
Find local comic book stores. Not only do they have impressive inventories of comic books and action figures, but their staffs are often fountains of knowledge. It is often obscure knowledge that will be more detailed than anything you'll find on the package.
Make your way to a comic book and/or toy convention. At places like this, it is often very likely that you will come face to face with the manufacturers and/or designers themselves.
Search book stores for books on the subject of action figure collecting. These books will not only offer stellar tips on maintaining and expanding a collection, but will also provide manufacturer listings and information.