Lots of information about x86 processors, including undocumented opcodes and bugs.

Archive of technical x86 processor information and downloadable documentation. Includes a discussion forum.

List of i386 specific information for IRQ's, and I/O addresses.

Book on Linux x86 assembly language programming which is available both in print and online under the GFDL license. Targetted to both new programmers and professional programmers who have not yet learned assembly language.

Assembler and Linux, source examples for Nasm and GAS assemblers.

For assembly programming newbies. Well written. Terse.

Assembly programming tutorials, references and on-line books. All searchable and free.

A reference for bugs and undocumented instructions in the Intel 80x86 family of processors.

Guide describes how to program in assembly using free programming tools, focusing on development for or from Linux OS on i386. By Francois-Rene Rideau 1996-1999, Konstantin Boldyshev 1999-2002.

Iteractive tutorial, using the Ketman Maximaster as a platform.