Apple has a code registration service which supplies more data if
you know a code, but does not list codes. Here is an extract from
Apple's FAQ:
Q - Will Apple give developers a list of Creator and File types
that have already been registered?
A - Unfortunately, no. We don't make the information in the
Creator/File Type Registration database available. You should be aware,
however, that you can use the search form to search the database to see
if a Creator type has been claimed.
Take a look at Apple's site
http://developer.apple.com/dev/cftype/faq.html (Points back to me
;-)