I want to access COM objects using Python 3.1, but I can't find a library to support 3.x. Do I need to use some extension or there is something in the standard library?
Try the PyWin stuff. It provides (among other things, like direct support for Win32 APIs) a COM bridge for Python and now supports both 2.x and 3.x.
Older downloadable releases are available here.
Documentation can be found here.