I have found the book 'Visual Basic Programmer's Guide to the Win32 API' useful. Don't be fooled by the Visual Basic part, it defines the parameters expected by the API in terms like '32 bit unsigned integer', etc. It covers all the core API routines (NO book covers all of them, there are over 8500 at last count, many are obscure, and they all change every 3rd OS revision or so).
I've experimented with the API and gotten good results. I'm attaching a set of functions so you can take em apart and look at them. They're made by LV 6i on Win98, but should work on most systems. If you need help, email me.
John Wilson
Sanders Engineering
Mobile, AL
johnwilson@pctechnician.net