Books, Links and Documentation
Peter Stadler has done a tremendous job by translating the example programs in Charles Petzold's book "Programming Windows 95" from Visual C++ to Modula-2, both for StonyBrook and XDS Modula-2. You can download the source from his site.
On line documentation
This site includes full Win32 API documentation and can be accessed freely. Before asking someone for help, do a search in MSDN first.
Win32 API Help file
This help file includes a complete overview and reference of the Win32 API.
C programming language Links
C programming language Books