This is a very broad question, which can hardly be answered in a forum posting. In fact, there are two books about system programming:

Intel 64 and IA-32 Architectures Software Developer's Manual

Volume 3A: System Programming Guide
Volume 3B: System Programming Guide

There are available for download here. Before you hit the print button, be warned that each of them is more than 800 pages long.

It is not easy to do an operating system. I dont know what are your abilities, but you need to know a lot of theory.

You you have a look to this book:

http://www.amazon.com/Modern-Operating-Systems-Andrew-Tanenbaum/dp/0136006639/ref=sr_1_2?ie=UTF8&s=books&qid=1275401908&sr=8-2-spell

http://www.amazon.com/Operating-Systems-Design-Implementation-3rd/dp/0131429388/ref=ntt_at_ep_dpi_3

http://www.amazon.com/Distributed-Operating-Systems-Andrew-Tanenbaum/dp/0132199084/ref=ntt_at_ep_dpi_6

Read this book from William stallings it will give you some idea about OS concepts and kernel development

http://williamstallings.com/OS/OS5e.html

Hello,

I'm also interested in this area. In the previous replies mentioned books are valuable. If you're more in examples I would recommend eg. DelphineOS which is written in FreePascal and shows a very basic but working 32-Bit OS (unfortunately the source is sometimes in french and it is only 32 Bit) but for learning and starting purposes (because language "Pascal") it is recommended.

Another resource is the Linux kernel Source Code and some good infos like

Concrete architecture of the Linux kernel (Open Press)
Linux kernel internals (Addison Wesley)
Linux CPU scheduler (somewhere on the net)

Holger