Online Assembly language resources [closed]

Question

does anyone have any resources for learning assembly language on x86? I'm trying to debug a program in MSVC++6 and frequently come across assembly (like stepping into memcpy).. Previously I just ignored these but memcpy keeps throwing exceptions and I need to find out why..

Any help would be appreciated :)

EDIT:Wow, lots of great resources.. I wish I could mark everything as accepted answer :P

HINT: combine anyone? :P

New edit: I just looked through the answers, and these seemed the best:

Aseraphim's post specific to intel x86

jkchong's post for a more introductory text

Answer 1

Online resources:

PC Assembly Language

Art of Assembly Language Programming

Answer 2

If you just need to understand what each instruction does, the reference manual for the IA-32 (x86) & IA64 instruction sets are located here.

Answer 3

Dunteman's "Assembly Language Step by Step" is a pretty good starting point for x86 assembly.

I'm sure there are good tutorial sites on the Net, but I'm not familiar with them.