Please check out FFI and C::Dynalib as well. They are not restricted to working on just Win32 and seem to have cleaner designs (though the APIs could use the addition of some helper functions to make things simpler).

Documentation of many APIs in Microsoft DLLs can be found by downloading the SDK (Software Developers' Kit) from Microsoft or buying a compiler. You might be surprised how many APIs are already available from Perl via modules.

        - tye (but my friends call me "Tye")