Accessing file metadata on windows XP

[wileyregister22 at gmail.com]

When rightclicking a, for example, pdf file on windows, one normally
gets a screen with three or four tags.  Clicking on one of the summary
tag one can get some info like "title", "Author", "category", "keyword"
etc..

My question is how can I programmatically read and change these data
with python.  I know I should use Hammond's win32  extension, somehow
involving the pythoncom, storagecon of win32com etc..  Unfortunately,
so far I cannot get anything useful.  Instead of trying blindly, would
somebody please points me to the correct direction.  A little snippet
would help.  I am particular interested in pdf files.