The Win32 implementations of Perl and Python more-or-less build in direct access to all of Microsoft's Win32 API(s). The APIs are a direct mapping of the APIs described in the SDK and (in APN's admittedly biased opinion) do not provide the kind of high level programming interface that is desirable in a scripting language.
Tcl provides access to Win32 APIs through extensions. See TWAPI, winapi and ffidl. The APIs are accessible through high level programming interfaces as well as using raw Win32 calls for masochists who like to work that way :-)
The no-charge version of bcc55 [...] includes a no-charge version of a reference to the Win32 API [...].
PT The entire Win32 API documentation is available from http://msdn.microsoft.com/library/
Windows API Reference [L1 ]
BR Note that the docs at the MSDN site do not include the actual values of manifest constants. This is a major source of grief for all Open Source projects dealing with the details of the Windows API. One could consider Microsofts actual headers as complementing the documentation in this regard, the headers are part of the SDKs which are available free of charge. But most projects fear to use or even just look at those because of possible copyright issues.
APN The constant values can also be obtained from the MinGW distributions if you do not want to look at the SDK.