To find out more try this on google.
MSDN WINDOWS XP TASK SCHEDULER
If you don't mean that but how the OS itself works there are tomes of books and articles out there along with a history of people who were involved in the development. This gives you an idea of what they were thinking when the OS kernel was designed.
Hi, I was wondering if anyone could give me an idea of where I could find some information on how scheduling systems work for Windows XP?